ATL: MATTHEW - Models

[Bocadude85]

I noticed this as well...the NAM gets no love regarding tropical systems but it is decent at picking up the overall synoptic pattern across North America.

The NAM and GFS really aren't all that far apart at 84 hours on their 0z run.

Mileage wise no...but forward motion and angle of approach is huge.

Agreed. It will be interesting to see when this makes the turn to the NW once in the Bahamas..the farther south then the closer to the Florida coast Matthew will get before passing by to the east..I could see the models shifting to Grand Bahama but no further west then that.

[sma10]

I noticed this as well...the NAM gets no love regarding tropical systems but it is decent at picking up the overall synoptic pattern across North America.

The NAM and GFS really aren't all that far apart at 84 hours on their 0z run.

Mileage wise no...but forward motion and angle of approach is huge.

Great point. As two dots on a map, the distance between the positions are quite reasonable margin off an 84 hr run. But for interests in SE Florida it may as well be a million miles.

[chaser1]

Okay, well this is a bit interesting and something that I think i'll take a look at a bit more closely as compared to tonights GFS 0Z run. As Alonyo mentioned a short while ago regarding the large trough moving eastward from the Pacific Northwest and Upper Plains, here is how the NAM projects this trough at 48 hours (click link: http://www.tropicaltidbits.com/analysis ... ypos=210.4 )

Now, fast forward to 72 hr.'s. What was a negativly tilted trough axis, has very quickly turned into a positive tilted trough axis (link: http://www.tropicaltidbits.com/analysis ... ypos=210.4 )

The mid level low over Montana seems to pull up and slowly NE. Meanwhile, the trough simply becomes broader and covering the western 2/3's of the CONUS, as new energy spills into the trough from the Pacific. Meanwhile it appears to me that increased ridging builds in from the W. Atlantic and also to the north of Matthew at this point. One can see the storm seemingly tracking along the N. Coast of Cuba and seemingly moving NW to a point over W. Andros Island in 84 hours and a much more threatening trajectory for S. Florida than the GFS or UK model. Oh, and before some begin throwing popcorn at their computer monitors, this has less to do with buying into a NAM hurricane forecast, as simply stating the fluid and evolving conditions that might well affect the storms forward motion.

I noticed this as well...the NAM gets no love regarding tropical systems but it is decent at picking up the overall synoptic pattern across North America.

Well, just to take this one step further. In comparing both 0Z runs of the NAM and GFS, the large previously negative tilt trough exists with both models as does the evolution to a positive tilt as well. Only major difference here (and I find this VERY interesting), is that there is a very significant difference in timing and that the GFS is WAY faster than the NAM. The GFS indicates the point where Matthew clears the N. Coast of Cuba will occur in 48 hrs. (and about 2-3 degrees further east than the NAM). Meanwhile the NAM brings Matthew just north of the Cuban coast in 63 hr.'s (and about 2-3 degrees west of the GFS solution). What I'm looking at has less to do with debating the two models and which might evolve to be inaccurately too far west or east (though this is important too); It appears to me that there may well be rising heights building in from the W. Atlantic, and as a result of the large W. CONUS trough remaining further west and in part due to its evolved positive tilt. Those additional 15 hours the NAM indicates Matthew might still be fairly far south appear to impact a greater northwesterly track than that of the more NNW tracks indicated by the GFS and UK models.

[SouthFLTropics]

Euro rolling...ridge appears stronger than last nights 00z.

[WHYB630]

Let's check the initial is correct or not
http://www.tropicaltidbits.com/analysis ... _atl_1.png

[sma10]

Okay, well this is a bit interesting and something that I think i'll take a look at a bit more closely as compared to tonights GFS 0Z run. As Alonyo mentioned a short while ago regarding the large trough moving eastward from the Pacific Northwest and Upper Plains, here is how the NAM projects this trough at 48 hours (click link: http://www.tropicaltidbits.com/analysis ... ypos=210.4 )

Now, fast forward to 72 hr.'s. What was a negativly tilted trough axis, has very quickly turned into a positive tilted trough axis (link: http://www.tropicaltidbits.com/analysis ... ypos=210.4 )

The mid level low over Montana seems to pull up and slowly NE. Meanwhile, the trough simply becomes broader and covering the western 2/3's of the CONUS, as new energy spills into the trough from the Pacific. Meanwhile it appears to me that increased ridging builds in from the W. Atlantic and also to the north of Matthew at this point. One can see the storm seemingly tracking along the N. Coast of Cuba and seemingly moving NW to a point over W. Andros Island in 84 hours and a much more threatening trajectory for S. Florida than the GFS or UK model. Oh, and before some begin throwing popcorn at their computer monitors, this has less to do with buying into a NAM hurricane forecast, as simply stating the fluid and evolving conditions that might well affect the storms forward motion.

I noticed this as well...the NAM gets no love regarding tropical systems but it is decent at picking up the overall synoptic pattern across North America.

Well, just to take this one step further. In comparing both 0Z runs of the NAM and GFS, the large previously negative tilt trough exists with both models as does the evolution to a positive tilt as well. Only major difference here (and I find this VERY interesting), is that there is a very significant difference in timing and that the GFS is WAY faster than the NAM. The GFS indicates the point where Matthew clears the N. Coast of Cuba will occur in 48 hrs. (and about 2-3 degrees further east than the NAM). Meanwhile the NAM brings Matthew just north of the Cuban coast in 63 hr.'s (and about 2-3 degrees west of the GFS solution). What I'm looking at has less to do with debating the two models and which might evolve to be inaccurately too far west or east (though this is important too); It appears to me that there may well be rising heights building in from the W. Atlantic, and as a result of the large W. CONUS trough remaining further west and in part due to its evolved positive tilt. Those additional 15 hours the NAM indicates Matthew might still be fairly far south appear to impact a greater northwesterly track than that of the more NNW tracks indicated by the GFS and UK models.

I think your logic is sound. However, it goes back to that old axiom: if my mother had wheels she'd be a bicycle.
I'm fairly confident that IF the gfs was slower and IF it was 2-3 degrees further west it would show a similar threat. I had thought about this exact scenario the past 2 days, that if the storm would unexpectedly slow down in the Caribbean, that it might impart a further west solution due to more ridging. And I thought that might have been what the uk was grabbing onto in the 12z. But the more superior models seem to be locked into this track for the time being.

[WHYB630]

00z EC t@48: sw of yesterday 00z

[SouthFLTropics]

Euro is SW of yesterday's 00z and appears to be SW of today's 12z.

[Kingarabian]

Stronger ridge than the 12z run @ 72hrs on the 00z Euro.

[chaser1]

I noticed this as well...the NAM gets no love regarding tropical systems but it is decent at picking up the overall synoptic pattern across North America.

Well, just to take this one step further. In comparing both 0Z runs of the NAM and GFS, the large previously negative tilt trough exists with both models as does the evolution to a positive tilt as well. Only major difference here (and I find this VERY interesting), is that there is a very significant difference in timing and that the GFS is WAY faster than the NAM. The GFS indicates the point where Matthew clears the N. Coast of Cuba will occur in 48 hrs. (and about 2-3 degrees further east than the NAM). Meanwhile the NAM brings Matthew just north of the Cuban coast in 63 hr.'s (and about 2-3 degrees west of the GFS solution). What I'm looking at has less to do with debating the two models and which might evolve to be inaccurately too far west or east (though this is important too); It appears to me that there may well be rising heights building in from the W. Atlantic, and as a result of the large W. CONUS trough remaining further west and in part due to its evolved positive tilt. Those additional 15 hours the NAM indicates Matthew might still be fairly far south appear to impact a greater northwesterly track than that of the more NNW tracks indicated by the GFS and UK models.

I think your logic is sound. However, it goes back to that old axiom: if my mother had wheels she'd be a bicycle.
I'm fairly confident that IF the gfs was slower and IF it was 2-3 degrees further west it would show a similar threat. I had thought about this exact scenario the past 2 days, that if the storm would unexpectedly slow down in the Caribbean, that it might impart a further west solution due to more ridging. And I thought that might have been what the uk was grabbing onto in the 12z. But the more superior models seem to be locked into this track for the time being.

I'm not sure about that analogy, and seem to think it was worded differently You have a good point. Of course it goes without saying, the further west the track - the greater the potential threat to Florida (and perhaps points north). I think more than anything though, it does go to show that very real implications could arise simply as a result of timing; More specifically how a distinctly slower hurricane might find itself tracking into a bit more of a wall than one moving quicker and into deeper and more southerly flow. By the way, as of 48 hours, the EURO has similarly cleared the N. Coast of Cuba (albeit slightly east of the GFS, but in tighter alignment with the GFS timing wise.)

[SouthFLTropics]

Euro at 96, much closer to Central Florida coastline. I smell a slight westward shift in track coming at 5:00AM.

[AutoPenalti]

Where's the thumb ridge that supposedly fills in?

[chaser1]

948mb at 96 hours, AND EURO looks a bit SW of its 12Z position
http://www.tropicaltidbits.com/analysis ... s=0&ypos=0

[SouthFLTropics]

948mb at 96 hours, AND EURO looks a bit SW of its 12Z position
http://www.tropicaltidbits.com/analysis ... s=0&ypos=0

It definitely is...the case is clear. The longer it takes Matthew to clear the Caribbean, the more in danger the SE CONUS is.

[chaser1]

Where's the thumb ridge that supposedly fills in?

Oh, I think your about to see it on the next frame (120 hours). Already closer the the Florida coast and increasing height anomalies too.

[Alyono]

EC MUCH faster this run, and has shifted west. Carolinas may not escape this run.

The trend is most certainly west tonight, except for the windshield wiping UKMET

[WHYB630]

00z EC t@96hrs: veeeerrry west vs 12z. And the trough seems to be a bit slower as well


(edited)
t@120: trough is weaker vs 00z GFS

[sma10]

948mb at 96 hours, AND EURO looks a bit SW of its 12Z position
http://www.tropicaltidbits.com/analysis ... s=0&ypos=0

Yes, this type of track is one that we were talking about, re: a slowing down in the Caribbean. And though further east slightly of the 12z UK, a bit similar.

I still tend to doubt that Matthew will get this close to Florida, but it's a perfectly plausible option.

[chaser1]

948mb at 96 hours, AND EURO looks a bit SW of its 12Z position
http://www.tropicaltidbits.com/analysis ... s=0&ypos=0

It definitely is...the case is clear. The longer it takes Matthew to clear the Caribbean, the more in danger the SE CONUS is.

Well, now i'm curious to see if whatever other model runs are seemingly lagging a bit longer in time, are now suddenly veering that much more northwestward toward the Florida coastline as well. Not that I have as much faith in the lessor models as compared to the EURO, GFS, and UK, but that would just go that much further to show what "could" happen should Matthew stall or take longer passing over mountainous terrain.

[SouthFLTropics]

Just slightly stronger ridging by the Euro and Matthew is riding the East Coast of Florida. Think Hurricane Charley in reverse. Close call there.