ATL: MATTHEW - Models

[Dylan]

12z GFS... Much weaker through 54 hours... Just N of W Movement...

it's a whole 2 mb weaker through 54 hours

Exactly. If anything it being weaker initially is worse for the US.

Development is a given at this point. The downstream synoptic pattern and how it effects this isn't...

[ronjon]

GFS 06z as discussed by others has that hard north turn between 70/75W and almost goes due north. Early Cycle 12z guidance doesn't go far enough out, but is that starting to smooth a little based on the ends of the late cycle 06z runs? 120 hours (5 days) is Sunday and is kind of the important day for a turn if you look at the GFS.

12z Early Cycle
https://www.ral.ucar.edu/hurricanes/rea ... _early.png

06z Late Cycle
https://www.ral.ucar.edu/hurricanes/rea ... k_late.png

That's a significant shift on the BAMM toward the GFDL solution. Would not be surprised to see the operational GFS follow suite soon.

[KWT]

It is a little weaker but that really won't mean much down the line, as long as the same basic set-up is aloft and it stays away from land, its going to strengthen.

Still no hint of the WSW bend as per most of the model guidance on the GFS. That bend to the WSW does look a little unusual but its not unheard of.

[chaser1]

It was about between 12Z and 18Z this upcoming Sat. when last nights GFS 0Z began turning this storm abruptly toward the north. Lets see if the GFS begins to come more in line with a further westward shift; I'd be really surprised if it didnt though. Better yet, watch the GFS suddenly go into all out "westward-ho Yucatan mode" lol.

[TheStormExpert]

12z GFS looks like it could be starting a cave towards the Euro?

[Blown Away]

12z GFS... 72 Hours... Strong TS/Cat 1... Maybe Just S Of N Now... Maybe??

[KWT]

12z GFS... 72 Hours... Strong TS/Cat 1... Maybe Just S Of N Now... Maybe??

South of west you mean?

Yes it sure looks like there is a touch of southerly motion in that track which would be a bit of movement towards the ECM solution if that occurs.

Important because it buys more time for the upper weakness to shut down and shunt this back NW/WNW as per Op ECM.

[Blown Away]

12z GFS... 72 Hours... Strong TS/Cat 1... Maybe Just S Of N Now... Maybe??

South of west you mean?

Yes it sure looks like there is a touch of southerly motion in that track which would be a bit of movement towards the ECM solution if that occurs.

Important because it buys more time for the upper weakness to shut down and shunt this back NW/WNW as per Op ECM.

Yes... Sorry

[PTrackerLA]

Significantly weaker out to 78 hours on 12z GFS...

[Blown Away]

12z GFS... 84 hours... Still just S of West... Cat 1

[KWT]

Back to due west by 84hrs.

Quite a bit weaker now than the 06z, which was down to 969mbs at this point (not sure where it is at, but probably low 980s high 970s from a ballpark, which also argues for a further west track.)

[Blown Away]

12z GFS... 90 hours... Moving W... Cat 1... Getting Stronger, 973 mb...

[PTrackerLA]

973mb at 90hrs vs 962mb and 950mb at 06z and 00z respectively. So trend is definitely weaker so far.

[TheProfessor]

The High in the Atlantic on the 12z GFS is a touch further west at 90 hours than it is on the 6z.

[CalmBeforeStorm]

Same strength and same position with close to the same setup as 6z run. Gotta assume this ends up the same in relation to departing the Caribbean

[chaser1]

Was 994mb right at about this time from the 0Z last night. From here out prior runs began that straight north turn and continued slow deepening.

[KWT]

Comparing the upper pattern, the 2 runs looks broadly the same, not spotting many differences at the moment other than 97L being weaker.

[TheStormExpert]

Still moving due west @96hrs.

[xcool22]

GFS COPY Euro MOVE

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[OntarioEggplant]

The GFS is starting to look much more like the Euro