ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[perk]

The discussion said it was a blend of the models, so I imagine now witha center, the models will pick sides, I lean towards the GFS and Euro personally.

"AFTER 72 HOURS THE TRACK MODEL GUIDANCE
DIVERGES...WITH ONE GROUP...INCLUDING THE HWRF AND GFDL...TAKING
THE SYSTEM ON A MORE NORTHERLY OR NORTHEASTERLY TRACK. A SECOND
GROUP OF GUIDANCE...INCLUDING THE GFS...ECMWF AND NOGAPS KEEPS THE
SYSTEM ON A MORE WESTERLY TRACK OVER THE SOUTHERN GULF OF MEXICO.
THE OFFICIAL FORECAST IS A BLEND OF THESE TWO."

AllI can say about this forecast is: I am holding my toungue for the sake of the young on the board. Many of you know my opinions about the NHC's "split the difference...consensus forecasts"...and this proves my point.

I guess I am just a pick a side type of guy.

AFM i have read enough of your post that i have a good idea of of what you think about the NHC's split the difference forecast. I would although be very interested in your opinion on where this system may be headed.

[clfenwi]

What is difference betweens Ships and Decay Ships?

Decay SHIPS accounts for the weakening effects of land, while SHIPS assumes everything is water.

[BigA]

That is an impressive hot tower. It's knocking at the stratosphere. Probably is Alex already, eager to see what recon says tonight.

[KWT]

Big ole convective burst there just as we finish off D-min...that'll probably only help to drag the pressures down lower as others have said, wouldn't shock me if we went below 1000mbs given its in a low pressure enviornment already and its got good convection over the top of the center.

[LaBreeze]

What is difference betweens Ships and Decay Ships?

Decay SHIPS accounts for the weakening effects of land, while SHIPS assumes everything is water.

Excellent question and answer!

[Ivanhater]

[HURAKAN]

Latest

[Aquawind]

CDOish..

[clfenwi]

As one would expect, the storm came up in today's Deepwater Horizon briefing. A bit of the pertinent Q&A:

Q: I didn’t actually hear though, who gets to make the call as to when the ships have to break and go and can you also give us the (inaudible)?

ADMIRAL ALLEN: I'm sorry, that would be the federal on-scene coordinator decision, as all of them are. But right now, the threshold for that decision nominally is the onset of gale-force winds in 120 hours, which is five days.

Male: And on survivability, can you translate that to the Simpson Scale on what it takes to get these ships to (inaudible)?


ADMIRAL ALLEN: Well, we're not even waiting, because you don't know—it could move into a 2, 3 or a 4 hurricane by the time it gets there. What we're looking at is gale-force winds, about 40 knots, onset of those, 120 hours in advance, storm moving that way, you start moving.

If you wait to get a clear delineation or the strength of the storm, you may be too late. And, again, the 120 hours is a time factor related to the onset of gale-force winds. Depending on the speed of the storm that could produce a different distance depending on how fast the storm is traveling.

A bit later on, he states that 120 hours is the maximum time they expect to need to break away recover vessels and go to safe harbor. That's a bit more comforting than the "3-7 day" estimate he gave a few days ago.

[Sanibel]

Make room on the bandwagon. We could see some action if that turns north and collects itself even more.


Slow brew wins it.

[HurricaneRobert]

Blending the models is really weird in this case. The outer lines seem to be the ones that are more likely.

[Dean4Storms]

One thing I think that keeps the intensity down on the HWRF and GFDL is the SW shear ahead of any strong trough. If they turn out right at least it looks like we would be dealing with a struggling TS.

[KWT]

That convective burst really is very close to the center of the system, its a shame recon isn't in there currently to get a good reading on the strength of TD1...wouldn't surprise me if I wake up tomorrow to TS Alex.

[KWT]

One thing I think that keeps the intensity down on the HWRF and GFDL is the SW shear ahead of any strong trough. If they turn out right at least it looks like we would be dealing with a struggling TS.

Yeah that is an issue, that being said if the upper trough is being overdone, esp in the 96hrs+ range, then we could end up seeing the system not actually getting hit by much in the way of shear at all...

[wx247]

I am surprised that there are no warnings out for Belize. Hmm...

[clfenwi]

That convective burst really is very close to the center of the system, its a shame recon isn't in there currently to get a good reading on the strength of TD1...wouldn't surprise me if I wake up tomorrow to TS Alex.

Given the data collected by recon and the intensification trend that seems to be apparent.... ...wouldn't be surprised to see TS Alex at the 11 PM advisory; especially if the TAFB 0Z Dvorak estimate is 2.5. (They went 2.0 for their 18Z estimate. SAB's 18Z estimate was only 1.0, so they would have to break constraint rules to have it at 2.5 for their 0Z estimate.

[JonathanBelles]

I am surprised that there are no warnings out for Belize. Hmm...

Because it was a not normally scheduled advisory, the NHC may not have had time to coordinate with Belize to issue the advisory.

[wzrgirl1]

They could always put out a special advisory right?

[bahamaswx]

Blending the models is really weird in this case. The outer lines seem to be the ones that are more likely.

Seems reasonable to me. Gives them more time to pick a side, and when they do the changes will be relatively consistent with the current forecast track, rather than a potentially massive swing.

[wxman57]

My track is a good bit faster across the Gulf and farther left, taking it inland about 110 miles south of Brownsville Wednesday late afternoon as a 70 mph TS. I don't buy the big slowdown and compromise track. It's guaranteed to be wrong. Will probably even track left of my track.