ATL: MATTHEW - Post-Tropical - Discussion

[Alyono]

This is embedded within the SAL. What we're seeing may be the convection bringing down the winds from the SAL easterly jet, which is usually around the 700 mb level

[NDG]

Yikes Peak 10-second Wind: 54 kt at 101°

I'm 50/50 with an upgrade even though they have not found a well defined LLC, IMO.
In another words I wouldn't be surprised either way

It has closed circulation, just not a well defined LLC.

[AdamFirst]

This is extremely strong for a disturbance, but in the tropics, speed can kill. It's just going too fast to get properly developed. It's just a matter of time though.

[CrazyC83]

The 50-55 kt sustained winds could still be significant for the Lesser Antilles though, even if there is no LLC...

[BensonTCwatcher]

OK, I take back my earlier comment that it is ramping up.
Convection is far removed from the wave axis.
I am going back with the idea that this slips underneath the forecasted Cut-Off Low's Trough.
I'll post something more technical on that idea later today on why I think it will likely miss the recurve and likely RI once it gets past the trough.

Most models don't really develop this into a TS until early Thursday morning. Once this gets going it will likely organize fairly quickly if shear is favorable as models indicate.

Yup, GFS does not show it really closed off till it gets to St Vincent or beyond ~( 13.5N 61.5W ) or thereabouts, so I just don't see that the intensity is affecting the model track solutions just yet

[gatorcane]

I don't think it warrants an upgrade yet. The longer this takes to develop, obviously better for Haiti but not so good for Jamaica/Cuba/Bahamas/Florida and possibly East coast of US further downstream. Remember the GFS was calling for a strong TS to hurricane by now in its runs from several days ago with a sharp recurve into the Dominican Republic/Haiti. GFS intensity forecast is not verifying.

[cycloneye]

The 50-55 kt sustained winds could still be significant for the Lesser Antilles though, even if there is no LLC...

Bingo my friend.

[Dean4Storms]

One thing for certain, if this does not slow down and fails to develop into a TC and deepen the next couple days it just might not react and turn as abruptly when the weakness forms off the Coast of Florida. We saw this with Hermine, models wanted to turn it northward as a TC in the Bahamas but the lack of development kept it caught in the lower level flow. The trades in the central Carib. Sea are still moving a good clip.

[centuryv58]

I don't think it warrants an upgrade yet. The longer this takes to develop, obviously better for Haiti but not so good for Jamaica/Cuba/Bahamas/Florida and possibly East coast of US further downstream. Remember the GFS was calling for a strong TS to hurricane by now in its runs from several days ago with a sharp recurve into the Dominican Republic/Haiti. GFS intensity forecast is not verifying.

This is my concern too. Westward ho seems to be the trend for the last few days with just a few wobbles off that track but definitely west.

[sma10]

This is extremely strong for a disturbance, but in the tropics, speed can kill. It's just going too fast to get properly developed. It's just a matter of time though.

Is this accurate? I have seen countless TC's over the years with forward speed of 15-20mph

[BensonTCwatcher]

Well the GFS and Euro don't forecast elongated and tilted circulations to that level detail, but 50+ kt winds seems pretty close to the models verify albeit the storm was depicted symmetrically. TS force winds at the surface and closed overall circ, dense increasing convection, heavy rains, high seas, all look like a TS to me despite the pressure ( which is relative), structure, and center not meeting the technical definition of the category.

[cajungal]

Still not of the question that it could still get in the Gulf.

[Dean4Storms]

This is extremely strong for a disturbance, but in the tropics, speed can kill. It's just going too fast to get properly developed. It's just a matter of time though.

Is this accurate? I have seen countless TC's over the years with forward speed of 15-20mph

It is if the system has winds impinging on it at the mid and upper levels from the West or WSW. It magnifies the shear, the LLC trying to form gets it upper level support blown away.

[Aric Dunn]

definitely enough convection to close off a circ just needs a little more time.

expect a shift west in the models.

[cycloneye]

 https://twitter.com/MichaelRLowry/status/781126637266010112

[sma10]

This is extremely strong for a disturbance, but in the tropics, speed can kill. It's just going too fast to get properly developed. It's just a matter of time though.

Is this accurate? I have seen countless TC's over the years with forward speed of 15-20mph

It is if the system has winds impinging on it at the mid and upper levels from the West or WSW. It magnifies the shear, the LLC trying to form gets it upper level support blown away.

Ok, thanks. So really it's the shear preventing the development, which is not uncommon. All academic anyway as all models agree this will eventually slow down significantly.
I think there is very little doubt this will become Matthew.

[Aric Dunn]

Clearly centered nearly right over Barbados and a little to the NW there is a weak surface reflection just seen on radar. question is is it enough for a upgrade. I think they will wait till 5pm. which by that time it will likely have a deepening LLV>

http://www.barbadosweather.org/RadarPro ... r_400KMSRI

[Gustywind]

The 50-55 kt sustained winds could still be significant for the Lesser Antilles though, even if there is no LLC...

is an euphemisma... that could pose trouble even if there's no LLC... all the activities outdoor etc.

[RL3AO]

I was curious so I went back a few days in the TWO.

2pm outlook from the 23rd - 0%/20%
2pm outlook from the 26th - 70%/90%

If we get genesis today, it will be another successful job from the NHC. It also tells you how far out 5 days is when it comes to making a genesis forecast.

[HurrMark]

This is extremely strong for a disturbance, but in the tropics, speed can kill. It's just going too fast to get properly developed. It's just a matter of time though.

I remember a tremendously strong wave in 1997 in the Caribbean that had sustained winds over 60 mph...but it was simply that...a wave. No west winds per recon. Never a named storm. Once it slows down, I think things will get cooking in a hurry.