ATL: MATTHEW - Models

[chaser1]

"Building Ridges and other Fun Ways to Pull Tropical Cyclones Poleward" - Found at bookstore everywhere lol

[Socalhurcnegirl227]

"Building Ridges and other Fun Ways to Pull Tropical Cyclones Poleward" - Found at bookstore everywhere lol

"Poleward Tropical Cyclones for Dummies" lol

[GCANE]

Latest GFDL is beginning to miss the trough again and looks to be heading west.

http://www.tropicaltidbits.com/analysis ... 0&ypos=200

Here is why:
As the vort column interacts with the trough, it will cause the vort column to tilt to the SE with increasing altitude.
This is the shape when a TC goes extra-tropical as opposed to a normally stacked TC.

You can see the effect on the latest GFDL forecasted phase diagram.



Without the trough, the graph would be more at a 45-degree slope.
The graph has a horizontal, blue component when the TC is interacting with the trough.
As the effects of the trough dissipate, the graph becomes more vertical - green component.
This is when the vort column kinda snaps back and becomes more stacked allowing the TC to reintensify.

You can get more insight on this under the Help/Docs section here:
http://moe.met.fsu.edu/cyclonephase/

Here is how the current GFS run is forecasting it.



Notice that it is just about 45 degrees to about Z where it begins to change to a more horizontal slope indicating extra-tropical transistion.

So, 355K PV is a good indication on how the trough interacts with the TC.
It indicates a pushing down of the troposphere or falling heights.
This creates an vorticity in the UL of the troposphere.
That vort interacts with the vort of the TC causing the TC's vort column to tilt.

How much of that is determined alot by mid-level moisture and convection in the vicintity.
Convection indicates an updraft which acts to push up the PV anomaly and lessen the effects of the TC vort column being tilted.

So, to make a long story short, a big variable in this is how much mid-level moisture is in the area when Matthew gets in the mid Carib.
This depends greatly on convection and the debris left behind.
My experience is that the models are totally devoid of this effect.
Its a wait and see at this point but is IMHO a key feature to watch for.

[GCANE]

COAMPS is a good model that takes more into account mesoscale development (parcle-lift, thuderstorm kinda stuff)

http://www.nrlmry.navy.mil/coamps-web/w ... 50&tau=999

It is showing a jog back to the NW just before Cuba.

[USTropics]

06z GFS running, slower this run, 15-20mb weaker as well:

06z at 78 hours:


00z same timeframe:

[jlauderdal]

COAMPS is a good model that takes more into account mesoscale development (parcle-lift, thuderstorm kinda stuff)

http://www.nrlmry.navy.mil/coamps-web/w ... 50&tau=999

It is showing a jog back to the NW just before Cuba.

trough lifting out, ridge building in plain as day on that model

euro seems to be playing catch up to gfs, will see what gfs does today...weaker storm implies farther west which should affect gfs runs today...MAYBE

[cycloneye]

 https://twitter.com/RaleighWx/status/781436811180638208

[CalmBeforeStorm]

COAMPS is a good model that takes more into account mesoscale development (parcle-lift, thuderstorm kinda stuff)

http://www.nrlmry.navy.mil/coamps-web/w ... 50&tau=999

It is showing a jog back to the NW just before Cuba.

trough lifting out, ridge building in plain as day on that model

euro seems to be playing catch up to gfs, will see what gfs does today...weaker storm implies farther west which should affect gfs runs today...MAYBE

GFS has been remarkably consistent over the last day or so with an Oct 5th position just east of the northern Bahamas and a consistent pattern solution. The Euro has been all over the place in position and pattern over the last day or so. I think the GFS has a much better handle on the situation.

[xironman]

LOL, divergence alright. Here is the 0z run of the GFS



Here is the 06z run



So where did that big upper low over Oklahoma come from?

[jlauderdal]

COAMPS is a good model that takes more into account mesoscale development (parcle-lift, thuderstorm kinda stuff)

http://www.nrlmry.navy.mil/coamps-web/w ... 50&tau=999

It is showing a jog back to the NW just before Cuba.

trough lifting out, ridge building in plain as day on that model

euro seems to be playing catch up to gfs, will see what gfs does today...weaker storm implies farther west which should affect gfs runs today...MAYBE

GFS has been remarkably consistent over the last day or so with an Oct 5th position just east of the northern Bahamas and a consistent pattern solution. The Euro has been all over the place in position and pattern over the last day or so. I think the GFS has a much better handle on the situation.

it was consistent until the run happening right now..lets see how it evolves..imagine if the euro ran every 6 hours..if setup correctly we would get a new model run every 3 hours between gfs and eueo..imagine the board traffic it would generate and aggressive comments between board members

[DESTRUCTION5]

1000+ mile difference still in location at 240 hrs between GFS and Euro. Something has gotta give.

[CalmBeforeStorm]

trough lifting out, ridge building in plain as day on that model

euro seems to be playing catch up to gfs, will see what gfs does today...weaker storm implies farther west which should affect gfs runs today...MAYBE

GFS has been remarkably consistent over the last day or so with an Oct 5th position just east of the northern Bahamas and a consistent pattern solution. The Euro has been all over the place in position and pattern over the last day or so. I think the GFS has a much better handle on the situation.

it was consistent until the run happening right now..lets see how it evolves..imagine if the euro ran every 6 hours..if setup correctly we would get a new model run every 3 hours between gfs and eueo..imagine the board traffic it would generate and aggressive comments between board members

Not seeing the present GFS run in the 144 hour range as inconsistent with previous recent runs

[SouthDadeFish]

Again, I think people are forgetting the time scale they are looking at with some of these long-range forecasts... Of course the solutions are going to be different at seven days! This is why people try to push the ensemble thinking so much. I do find it interesting that there was a pretty sizable shift eastward in the ECMWF ensembles on the 00Z cycle. Also, large timing differences between the EC and GFS remain.

[GCANE]

LOL, divergence alright. Here is the 0z run of the GFS

So where did that big upper low over Oklahoma come from?

Just popped up, coming in from the Pacific.
Pretty healthy.

[chris_fit]

Good Morning everyone.

Per Model Trend and recent recon fix, it appears that the threat to FL/GULF appears to be decreasing. Matthew is a little north of forecast points and both EURO and GFS keep it a decent distance away from the FL Coast. NC is another story however. Chances of a stall around the bahamas and then a west push appear to be decreasing per GFS and EURO.

[SouthFLTropics]

FWIW, the 06z HWRF Is a full degree SW of the 00z run.

[CalmBeforeStorm]

Good Morning everyone.

Per Model Trend and recent recon fix, it appears that the threat to FL/GULF appears to be decreasing. Matthew is a little north of forecast points and both EURO and GFS keep it a decent distance away from the FL Coast. NC is another story however. Chances of a stall around the bahamas and then a west push appear to be decreasing per GFS and EURO.

Not buying that here in Florida. Until GFS trends east nothing has changed as its been consistent with a position just east of the northern Bahamas and it has slowed a bit. The Euro has been very inconsistent and still shows an almost stall above the DR with a really strong ridge building in which, if the storm had been in the GFS position, would have driven Matt towards Florida. Too early to tell yet one way or the other.

[tolakram]

0Z EUro run. Yet another solution at 500mb

[chris_fit]

Good Morning everyone.

Per Model Trend and recent recon fix, it appears that the threat to FL/GULF appears to be decreasing. Matthew is a little north of forecast points and both EURO and GFS keep it a decent distance away from the FL Coast. NC is another story however. Chances of a stall around the bahamas and then a west push appear to be decreasing per GFS and EURO.

Not buying that here in Florida. Until GFS trends east nothing has changed as its been consistent with a position just east of the northern Bahamas abs has slowed a bit. The Euro has been very inconsistent and still shows an almost stall above the DR with a really doe building in which, if the storm had been in the GFS position, would have driven Matt towards Florida. Too early to tell yet one way or the other.

I agree, definitely not out of the woods by any means, take a look at the GFDL for example, but I would argue the threat to FL appears to be 'less than yesterday'

[tolakram]

6Z GFS