ATL: GERT - Post-Tropical - Discussion

[cycloneye]

00z Best Track:

As of 00:00 UTC Aug 06, 2017:

Location: 10.5°N 39.0°W
Maximum Winds: 25 kt Gusts: N/A
Minimum Central Pressure: 1010 mb
Environmental Pressure: 1013 mb
Radius of Circulation: 180 NM
Radius of Maximum Wind: 100 NM

[AutoPenalti]

Are we really going to trust models at this moment when a system is just now consolidating...

[AtlanticWind]

Are we really going to trust models at this moment when a system is just now consolidating...

We will just have to see how the models react over the next day or two

[txwatcher91]

Looking a bit better but the wave axis is still tilted too much. It will be a race to see if it can consolidate before hitting the wall of shear near the islands. If it manages to pass north of them and find a favorable environment then it could be a quick spin up.

[StormTracker]

Actually, there is more vorticity with 99L than 90L currently. It has been consolidating all day long just like 90L.

The difference is, 90L is in a more favorable area for development, but we'll soon see.

[AtlanticWind]

I noticed that several of the GFS ensemble members that get 99L north of the islands still develop this,
the story on this system may not quite be over yet.

[weathaguyry]

With a system acting the way this one is, it is foolish to deny that it is forming because models don't say it will.

[Hurricaneman]

With a system acting the way this one is, it is foolish to deny that it is forming because models don't say it will.

We've seen in the past systems that got dropped by the models just to form anyway just thinking back to Joaquin in 2015 the models didn't expect much and it became a near cat 5 hurricane so I'm not writing this one off until it's either taken away into the North Atlantic or inland or completely sheared away

[TheStormExpert]

If anything the 18z GFS seemed like it wanted to develop it more when compared to the 12z run, but who knows especially with the way that model has behaved as of lately.

[Kingarabian]

Don't get fooled by 99L and its intermittent pulsing convection. TW's are capable of doing this and they do it quite often thus giving out false positives. Overall environment still isn't very conducive.

[txwatcher91]

Don't get fooled by 99L and its intermittent pulsing convection. TW's are capable of doing this and they do it quite often thus giving out false positives. Overall environment still isn't very conducive.

It has a long ways to go, but it has an anticyclone building overhead per CIMSS analysis and has some decent convection finally popping. It doesn’t have a lot of time though before hitting the wall of shear in front of it, but if that weakens or lifts out then who knows.

[USTropics]

A building anticyclone will certainly help negate some of the shear associated with the Potential Vorticity streamer to the north. When dealing with PV streamer enduced shear, the key difference in synoptic-scale flow between developing and nondeveloping tropical systems is often the strength of the anticyclone north of the tropical disturbance. When/if development occurs, it's often marked by a stronger near-surface pressure gradient and attendant easterly flow north of the vortex, which drives enhanced surface latent heat fluxes and westward (upshear) water vapor transport. This evolution in water vapor facilitates an upshear propagation of convection, and the diabatically influenced divergent outflow erodes the PV streamer aloft by negative advection of PV by the divergent wind.

[SouthFLTropics]

Don't turn your back on 99L...the Euro is bringing it back on tonight's 00z run with a much more defined vort north of Hispaniola.

[bamajammer4eva]

00z Euro

[HurricaneEric]

Euro brings the remnants of 99L back to life a bit at hour 168 of the 00z run. Down to 1011mb low just north of the southern Bahamas.

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[Siker]

The saga of Hermine 2.0 continues. CMC intensifies in the same area. UKMET also develops late further north:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 144 HOURS
FORECAST POSITION AT T+144 : 25.8N 66.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 12.08.2017 144 25.8N 66.8W 1011 35

[AxaltaRacing24]

This might not blow up into the major hurricane that the GFS showed, but the 00z Euro shows that this still needs to be watched down the road.

[SouthFLTropics]

Euro 216 hours shows a pretty good storm east of the northern Bahamas.

[HurricaneEric]

00z Euro forms TS Gert (1003mb) at hour 216

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[AtlanticWind]

Euro 00Z is just one run,but this is why it is not wise to write off strong waves this time of year.
All they need is to find a sweet spot and something can happen really quickly.