ATL: NATE - Post Tropical - Discussion

[Javlin]

NAM32 @69hr has H now I am looking at the NAM more for location not so much intensity but will take notice if some other models change their tune.

https://www.tropicaltidbits.com/analysi ... 0&ypos=228

[Aric Dunn]

NAM32 @69hr has H now I am looking at the NAM more for location not so much intensity but will take notice if some other models change their tune.

https://www.tropicaltidbits.com/analysi ... 0&ypos=228

honestly the NAM track is showing the interaction of the 2 low pressures... I dont think we will see a NNE motion with nate but the idea of the nam is reasonable given the likelyhood of interaction between the 2 lows.

[NDG]

on a side note.... the 06 GFS has the system north of cuba moving WNW to NW from this point on.. however it is moving due west if not slightly south of west.. reason for this post.. the shear drops off in about 24 to 30 hours just north of CUBA and the Yucatan channelas upper ridging builds back in.. if this stays farther south it may end up even actually getting a classification.. greatly affecting Nate... need to watch the track of the circ associated with the noname system.

If anything the little swirl is dying out this morning and is it is rotating around a larger broad and weak circulation.

[Aric Dunn]

on a side note.... the 06 GFS has the system north of cuba moving WNW to NW from this point on.. however it is moving due west if not slightly south of west.. reason for this post.. the shear drops off in about 24 to 30 hours just north of CUBA and the Yucatan channelas upper ridging builds back in.. if this stays farther south it may end up even actually getting a classification.. greatly affecting Nate... need to watch the track of the circ associated with the noname system.

If anything the little swirl is dying out this morning and is it is rotating around a larger broad and weak circulation.

huh?

nothing dying out about it.. and not rotating around anything.. so not sure what your saying. its also not just a little swirl.. its has become quite a bit more expansive overnight.

[Javlin]

NAM32 @69hr has H now I am looking at the NAM more for location not so much intensity but will take notice if some other models change their tune.

https://www.tropicaltidbits.com/analysi ... 0&ypos=228

honestly the NAM track is showing the interaction of the 2 low pressures... I dont think we will see a NNE motion with nate but the idea of the nam is reasonable given the likelyhood of interaction between the 2 lows.

That's kind of the hard part to not accept Aric it always happens this time of the year.You could be right though maybe a different pattern setup.

[MGC]

11am advisory has a 80mph cane right over me Sunday morning.....MGC

[NDG]

on a side note.... the 06 GFS has the system north of cuba moving WNW to NW from this point on.. however it is moving due west if not slightly south of west.. reason for this post.. the shear drops off in about 24 to 30 hours just north of CUBA and the Yucatan channelas upper ridging builds back in.. if this stays farther south it may end up even actually getting a classification.. greatly affecting Nate... need to watch the track of the circ associated with the noname system.

If anything the little swirl is dying out this morning and is it is rotating around a larger broad and weak circulation.

huh?

nothing dying out about it.. and not rotating around anything.. so not sure what your saying. its also not just a little swirl.. its has become quite a bit more expansive overnight.

Is basically a naked swirl now, I remember last night it was tracking WNW if not NW while this morning is heading more WSW.

[Ken711]

Tropical Storm Nate Discussion Number 5
NWS National Hurricane Center Miami FL AL162017
1100 AM EDT Thu Oct 05 2017

The cloud pattern associated with Tropical Depression Sixteen
increased in organization after the last advisory, with the
formation of a ragged central convective feature and outer banding
in the northeastern semicircle. In addition, data from the
Colombian radar at San Andres showed a partial eyewall, and surface
observations from Puerto Cabezas, Nicaragua, included a pressure of
1001 mb outside of the center. Based on these data, the initial
intensity has been increased to 35 kt, and the depression has been
upgraded to Tropical Storm Nate.

The center of Nate is now inland over northeastern Nicaragua, and
little change in strength is expected until the center moves over
the northwestern Caribbean Sea. After that, a combination of warm
sea surface temperatures and light shear should allow for at least
steady strengthening. However, the guidance is producing mixed
signals despite a favorable-looking environment. The Rapid
Intensification Index of the SHIPS model is showing high chances of
rapid intensification, with better than a 50 percent chance of 25
kt of strengthening in the next 24 h and nearly a 50 percent chance
of 65 kt of strengthening in 72 h. On the other side, the GFS and
Canadian models show only modest development and keep the cyclone
as a tropical storm until it reaches the northern Gulf coast.
Given the environment, the intensity forecast leans towards the high
end of the guidance envelope and calls for Nate to become a
hurricane in about 48 h and reach the northern Gulf Coast as a
hurricane.

The initial motion is 325/8. A combination of a large cyclonic gyre
over Central America, a trough of low pressure moving westward
across the Gulf of Mexico, and a building subtropical ridge over
the western Atlantic should steer Nate generally north-northwestward
with an increase in forward speed during the next 72 h. While the
guidance is in better agreement on the direction that Nate should
move, there remains disagreement on the speed despite an overall
trend toward a faster motion. The new forecast track is similar to
the direction of the previous track, but shows a faster forward
speed that has the center near the northeastern Yucatan Peninsula
in about 36 h and near the northern Gulf Coast in about 72 h.
After the Gulf Coast landfall, Nate or its remnants are expected to
recurve northeastward upon encountering the mid-latitude
westerlies.


KEY MESSAGES:

1. Heavy rainfall is the main threat from Nate in portions of
Central America, with life-threatening flash flooding and mud slides
possible in portions of Nicaragua, Honduras, Costa Rica, Panama, and
Belize through Friday night.

2. Nate is forecast to be near hurricane intensity when it
approaches the Yucatan Peninsula late Friday, bringing direct
impacts from wind, storm surge, and heavy rainfall. A tropical storm
warning and a hurricane watch are in effect for a portion of this
area and life-threatening flash flooding is also possible.

3. Nate is forecast to reach the northern Gulf Coast this weekend as
a hurricane, and the threat of direct impacts from wind, storm
surge, and heavy rainfall is increasing. However, it is too early
to specify the exact timing, location, or magnitude of these
impacts. Residents along the Gulf Coast from Louisiana through the
Florida Panhandle should monitor the progress of Nate and heed any
advice given by local officials.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 14.3N 83.7W 35 KT 40 MPH...INLAND
12H 06/0000Z 15.6N 84.3W 35 KT 40 MPH...INLAND
24H 06/1200Z 18.1N 85.4W 45 KT 50 MPH...OVER WATER
36H 07/0000Z 20.8N 86.8W 55 KT 65 MPH
48H 07/1200Z 23.7N 88.1W 65 KT 75 MPH
72H 08/1200Z 29.5N 89.5W 70 KT 80 MPH
96H 09/1200Z 36.0N 85.0W 30 KT 35 MPH...INLAND
120H 10/1200Z 41.5N 76.5W 20 KT 25 MPH...POST-TROP/INLAND

$$
Forecaster Beven

NHC bumped up the intensity at 72H slightly.

[Aric Dunn]

If anything the little swirl is dying out this morning and is it is rotating around a larger broad and weak circulation.

huh?

nothing dying out about it.. and not rotating around anything.. so not sure what your saying. its also not just a little swirl.. its has become quite a bit more expansive overnight.

Is basically a naked swirl now, I remember last night it was tracking WNW if not NW while this morning is heading more WSW.

yes convection is limited. though the pressures continued to drop and the pressure field expanded and the circulation is much larger.. that is very important when it comes to nate..

[stormlover2013]

yeah I just watch stormgeo, hebert said he see's a circulation and it will play a major part

[bella_may]

Looks like the center is headed straight for me

[Big Easy Breeze]

How about that, the Euro now looks more like the crazy GFS runs.

[i mg]https://i.imgur.com/WoPD61a.gif[/img]

What is crazy?

Hi Big Easy,

this is the models thread so we discuss model runs. This is not the place to try and get an accurate forecast. Not saying questions aren't welcome but just reminding that this thread is different from the discussion thread.

Last nights run of the GFS (the one I was commenting on) had all kinds of convective feedback issues, showing numerous areas of vorticity impossibly close to each other. The Euro run is now very close to the track the GFS showed and also shows one competing low level circulation. In addition the Euro now shows the low developing in the Florida straits and moving north west. Regardless of the horrible feedback issue will the GFS end up being more accurate with Nate? That's the big question right now.

I was just wondering what your "crazy" reference was directed to. Not trying to disect a forecast.

[stormlover2013]

still plenty of time bella, by the euro, cmc, gfs, it's saying center wont be going straight for you but you still have time to watch

[bella_may]

still plenty of time bella, by the euro, cmc, gfs, it's saying center wont be going straight for you but you still have time to watch

Landfall is usually 50 miles east or west of where it's projected this far out lol. I'd say east if I had to bet

[kevin mathis]

From Levi (Tropical Tidbits) yesterday, Levi discussed the differences in the GFS and Euro 12z runs. He stated we could know this AM which was more accurate. His comments were the GFS and it models run off the GFS showed a stronger signature to the feature in the straits compared to the Euro. Additionally the Euro would be somewhat verifiable by this AM if there was a northward moving area of heavier precipitation/signature in the northern end of the trof axis offshore the East coast of Florida. Both seem to have come to fruition. The feature south of Key West is still sheared and an OPEN wave ...it was modeled to be closed off. Additionally, the enhanced rain is off the east coast, he continued, this would help promote height drops which could eventually help weaken the ridge to some degree. That was the notable differences in the 2 runs. I know the Euro swung well west in its last run, but does anyone think since it appears it was on to something from its 12z yesterday that it may bring that baroclinic pressure falls idea back into play in future runs?

[gatorcane]

Less interaction with Nicaragua/Honduras on 12Z GFS so the storm is already stronger by hour 12.

[stormlover2013]

high pressure is still strong on the gfs run

[Blown Away]

From Levi (Tropical Tidbits) yesterday, Levi discussed the differences in the GFS and Euro 12z runs. He stated we could know this AM which was more accurate. His comments were the GFS and it models run off the GFS showed a stronger signature to the feature in the straits compared to the Euro. Additionally the Euro would be somewhat verifiable by this AM if there was a northward moving area of heavier precipitation/signature in the northern end of the trof axis offshore the East coast of Florida. Both seem to have come to fruition. The feature south of Key West is still sheared and an OPEN wave ...it was modeled to be closed off. Additionally, the enhanced rain is off the east coast, he continued, this would help promote height drops which could eventually help weaken the ridge to some degree. That was the notable differences in the 2 runs. I know the Euro swung well west in its last run, but does anyone think since it appears it was on to something from its 12z yesterday that it may bring that baroclinic pressure falls idea back into play in future runs?

JMHO... Nate will be a weak, sheared TS, with all the convection on the east side, and landfall between N.O. and Pensacola...

[psyclone]

yeah I just watch stormgeo, hebert said he see's a circulation and it will play a major part

Does that mean a change in the projected track? I'm pretty sure the folks at the NHC can see the naked swirl heading through the straits and have accounted for it in their projections.

[Sanibel]

Caught a good chunk of Honduras and should be retarded because of it...


Coolish air down here doesn't feel totally hurricane conducive...