Global Models for 90L

[RL3AO]

Defiantly a weird run.

[KFDM Meteorologist]

CMC goes north.

CMC or whatever that model is looks crazy turning that north into the ridge.

[mgpetre]

To the untrained eye 90L looks like the first CV (perhaps the first in the Atl period) to have all the characteristics of a TD/TS... doesn't this have some bearing over all models as far as development for now?

[clfenwi]

The GFDL did a similar thing on a run that occurred 12 hours before the TD that became Ernesto was classified. Jeff Masters posted an email from one of the GFDL creators on what happened

The vortex initialized from our initialization was very weak as the initialization process spins up the storm to match the observed initial winds. Since the easterlies in the lower level were very strong in the GFS analysis, it initialized a disturbance with very weak vorticity.

As you can see at hour 0 there was almost no circulation initially. As a result, our grid movement shut down at 3 hours and the inner nests could no longer follow the storm for the rest of the forecast.

The previous runs also had a very weak initial disturbance but there was enough of a pressure gradient that the inner nests continued to follow the vortex and eventually with the high resolution it developed into a significant tropical cyclone.

In the 6z run, the weak disturbance moved out of the high resolution inner grid, into the coarse resolution, and so all we had left was a very weak disturbance that could not be resolved in the coarse outer mesh.

(source)

No telling if the same thing happened in this case, but it was probably similar and not much should be read into it.

[mgpetre]

The GFDL did a similar thing on a run that occurred 12 hours before the TD that became Ernesto was classified. Jeff Masters posted an email from one of the GFDL creators on what happened

The vortex initialized from our initialization was very weak as the initialization process spins up the storm to match the observed initial winds. Since the easterlies in the lower level were very strong in the GFS analysis, it initialized a disturbance with very weak vorticity.

As you can see at hour 0 there was almost no circulation initially. As a result, our grid movement shut down at 3 hours and the inner nests could no longer follow the storm for the rest of the forecast.

The previous runs also had a very weak initial disturbance but there was enough of a pressure gradient that the inner nests continued to follow the vortex and eventually with the high resolution it developed into a significant tropical cyclone.

In the 6z run, the weak disturbance moved out of the high resolution inner grid, into the coarse resolution, and so all we had left was a very weak disturbance that could not be resolved in the coarse outer mesh.

(source)

No telling if the same thing happened in this case, but it was probably similar and not much should be read into it.

This is a particular case in which I believe we can argue for the strength of neural networks over that of state machines...

[Scorpion]

I'm not buying into any of these excuses... when two very notable models all of a sudden drop a system they do so for a reason.

[mgpetre]

I'm not buying into any of these excuses... when two very notable models all of a sudden drop a system they do so for a reason.

So are you banking on the models and agreeing that this storm will be dead on arrival? I am willing to place a pretty large wager that you would be wrong with the models on that one.

[Cyclenall]

I'm not buying into any of these excuses... when two very notable models all of a sudden drop a system they do so for a reason.

It's most likely a glitch since the model didn't even initialize anything even though this is most likely a TD right now. I highly doubt the model would dump the system like that so rapidly out of nowhere. I was wondering if the fact that it's not a TD officially will affect the models too much even though it could be one right now?

I think the HWRF was a bit late, and it shows a hurricane still. This further makes me believe the latest GFDL run was garbage.

[Brent]

I'm not buying into any of these excuses... when two very notable models all of a sudden drop a system they do so for a reason.

Not this again...

and the Euro run was 12 hours ago, let's see what the 0z shows.

[Extremeweatherguy]

I'm not buying into any of these excuses... when two very notable models all of a sudden drop a system they do so for a reason.

Not this again...

and the Euro run was 12 hours ago, let's see what the 0z shows.

yeah, plus I wouldn't really call the EURO "reliable" when it comes to tropical cyclones. Upper-level condition, yes..but tropical storms and hurricanes...no.

[clfenwi]

00Z HWRF did not drop it.

Interesting to compare the initial conditions of the HWRF compared to the GFDL. The HWRF started with a minimum pressure of 1006 millibars, which just so happens to match the pressure that was reported in the TWD. On the other hand, the GFDL started with a pressure of 1010 millibars. That under-initialization is probably what caused the GFDL to lose the disturbance.

[Brent]

00Z HWRF did not drop it.

Interesting to compare the initial conditions of the HWRF compared to the GFDL. The HWRF started with a minimum pressure of 1006 millibars, which just so happens to match the pressure that was reported in the TWD. On the other hand, the GFDL started with a pressure of 1010 millibars. That under-initialization is probably what caused the GFDL to lose the disturbance.

and still shows a hurricane for the islands.

I think you're right about the different initializations in intensity.

[Scorpion]

The Euro should be coming out soon... the results should be very foreboding on the future of this system

[Vortex]

when will the EURO be out???

[Scorpion]

I believe it comes out around 3:30

[KFDM Meteorologist]

Please post it when it comes out. I have to sleep now and will look at it tomorrow morning..LOL

[wxmann_91]

Well well well...



Weak system, continues the trend of weaker.
And a second system in the open Atlantic.

500mb shows ridge to the north which will allow this to move into the GOM, extrapolating past 240hr.

[Scorpion]

At least it develops it this time.. last run just killed it off

[flwxwatcher]

EURO is slower then the GFS with this storm and further North . btw, Here is a a nice read about model verification for the 2006 hurricane season.

http://www.nhc.noaa.gov/verification/pd ... n_2006.pdf

[vaffie]

The 00Z WRF run has the same exact speed as the previous two runs--reaching 62W at 18Z on 17 August, but is much further south at that point at 14.4N (vs 15.8N and 15.3N) and stronger at 971 mb (vs 990 and 980)

.