ATL: HARVEY - Post-Tropical - Discussion

[wxman57]

LEVI said it's still closed!

Remain calm. There appears to be a poorly-defined, but closed circulation. Maybe even more than one center. It's going to have a hard time organizing until it passes the eastern Caribbean and the trades slow down.

[GCANE]

Its really rockin St Vincent

[GCANE]

 https://twitter.com/OnlyRiverP/status/898538894861402112

[Tireman4]

LEVI said it's still closed!

Remain calm. There appears to be a poorly-defined, but closed circulation. Maybe even more than one center. It's going to have a hard time organizing until it passes the eastern Caribbean and the trades slow down.

You are thinking....Monday or Tuesday for a handle on this...letting the models work itself out?

[xironman]

Quite the difference with SFMR

Peak (10s) Flt. Lvl. Wind: 6 kts (6.9 mph)
SFMR Peak (10s) Sfc. Wind: 35 kts (40.3 mph)

[wxman57]

You are thinking....Monday or Tuesday for a handle on this...letting the models work itself out?

I don't trust the GFS with its upper air pattern beyond 3-4 days. The ECMWF is very inconsistent from run to run, which isn't giving me much confidence either. The UKMET, which often does well with TCs, buries Harvey in southern Mexico. I'm still forecasting an emergence into the BoC next Wednesday afternoon (or so) then westward into Mexico (south of Tampico). However, I wouldn't declare the NW Gulf "safe" by any means. Long-range ensemble guidance indicates a 10% chance of a south Texas impact (from tropical storm-force winds, not necessarily the center). If I were you, I'd give my hurricane kit another look and make sure everything is there and ready to go - just in case.

That goes for any of you from Texas to Louisiana. You should have your kit ready to go at the beginning of the season, but now would be a good time to make sure it's OK.

I'll feel more confident as to the final landfall once the models are in much better agreement. Hopefully by Monday. Maybe earlier.

[euro6208]

Its really rockin St Vincent

I've seen much more impressive videos than this or maybe you are talking about the location about how it's rarely getting affected thus impressive?

[Blown Away]

12z.. Looks like a small window of low shear just before CA and then shear picks up after that...

[Tireman4]

You are thinking....Monday or Tuesday for a handle on this...letting the models work itself out?

I don't trust the GFS with its upper air pattern beyond 3-4 days. The ECMWF is very inconsistent from run to run, which isn't giving me much confidence either. The UKMET, which often does well with TCs, buries Harvey in southern Mexico. I'm still forecasting an emergence into the BoC next Wednesday afternoon (or so) then westward into Mexico (south of Tampico). However, I wouldn't declare the NW Gulf "safe" by any means. Long-range ensemble guidance indicates a 10% chance of a south Texas impact (from tropical storm-force winds, not necessarily the center). If I were you, I'd give my hurricane kit another look and make sure everything is there and ready to go - just in case.

That goes for any of you from Texas to Louisiana. You should have your kit ready to go at the beginning of the season, but now would be a good time to make sure it's OK.

I'll feel more confident as to the final landfall once the models are in much better agreement. Hopefully by Monday. Maybe earlier.

Got it. Thanks...that is what I was thinking, but I am not a pro met. Srain was saying the same thing, so you two are thinking alike.

[GCANE]

Its really rockin St Vincent

I've seen much more impressive videos than this or maybe you are talking about the location about how it's rarely getting affected thus impressive?

That video was about 1/2hr before the heavy convection hit them.

[GCANE]

 https://twitter.com/TTWeatherCenter/status/898543957713575936

[Gustywind]

Here are some videos from Barbados. Harvey is there! Numerous floodings could be seen!
https://www.youtube.com/watch?v=VTLbY5Gbc-U
https://www.youtube.com/watch?v=CnnMAqmfz5c

LIGHTNING from tropical storm HARVEY over Barbados Aug 18 2017
https://www.youtube.com/watch?v=fORxiob_7U4
Very Impressive lightnings from Barbabos
Hope Barbados is safe and dry. My best thoughts are with you Abajan.

[ROCK]

Uptick in lat continues...can't wait to see the Euro later today..very excited..

https://my.sfwmd.gov/portal/pls/portal/ ... RM_DISPLAY

[Tireman4]

Uptick in lat continues...can't wait to see the Euro later today..very excited..

https://my.sfwmd.gov/portal/pls/portal/ ... RM_DISPLAY

But what of the Navy Rock? We cannot forget the Navy!!

[Blown Away]

MeteoMark very optimistic about Harvey/92L...
https://www.youtube.com/watch?v=R_w_Y0-ndOE

[Gustywind]

For those who think that a small TS is a joke at the scale of a small island...Another videos showing the big floodings in Barbados!
https://www.youtube.com/watch?v=Yfvw873Husc
https://www.youtube.com/watch?v=AadhyTqMEYo
https://www.youtube.com/watch?v=tQJijHvGu-Y
https://www.youtube.com/watch?v=ZLM3jX7pHuQ

[cycloneye]

Tropical Storm Harvey Discussion Number 5
NWS National Hurricane Center Miami FL AL092017
1100 AM AST Fri Aug 18 2017

The structure of Harvey has changed little during the past several
hours, and overall the storm is poorly organized. The low-level
center is near the eastern edge of the convective mass due
to the affects of 15 kt of vertical wind shear. In addition,
surface observations and Air Force Reserve Hurricane Hunter data
suggest that the 850-mb center is located west or southwest of the
surface center. Based on the aircraft and surface data, the central
pressure is near 1005 mb and the initial intensity remains 35 kt.

The initial motion is a quick 270/18. A strong low- to mid-level
ridge north of the cyclone should keep Harvey on this general motion
for the next 3-4 days, with the system moving from the eastern to
the western Caribbean Sea during this time. Late in the forecast
period, a more northerly motion is expected when Harvey passes near
or over portions of Central America, the Yucatan Peninsula, and
eastern Mexico. The new forecast track remains in the center of the
guidance, and only minor changes were made to the previous track.

The current shear should persist for the next 48 h or so, and thus
the intensity forecast continues the trend of slow strengthening
during this time. After that, conditions appear favorable for
strengthening, with the main uncertainty being how much land Harvey
will encounter. The ECMWF keeps the cyclone a little north of
Nicaragua and Honduras and allows more room for development, while
the GFS forecasts landfall in northeastern Nicaragua and thus has a
weaker intensity. The new NHC forecast is close to the previous
one in showing a peak intensity below hurricane strength, but
the confidence in this portion of the forecast is low.

FORECAST POSITIONS AND MAX WINDS

INIT 18/1500Z 13.1N 61.3W 35 KT 40 MPH
12H 19/0000Z 13.3N 63.8W 35 KT 40 MPH
24H 19/1200Z 13.6N 67.3W 40 KT 45 MPH
36H 20/0000Z 14.0N 71.1W 40 KT 45 MPH
48H 20/1200Z 14.3N 75.0W 50 KT 60 MPH
72H 21/1200Z 15.0N 82.0W 60 KT 70 MPH
96H 22/1200Z 16.5N 87.5W 55 KT 65 MPH
120H 23/1200Z 18.5N 91.0W 30 KT 35 MPH...INLAND

$$
Forecaster Beven

[GCANE]

Highest SFMR: 56 knots
13:56:30Z 13.000N 61.550W

[MississippiWx]

Definitely hasn't opened up according to recon. Just tilted due to some northeasterly shear.

Really ? It looks open

http://i.imgur.com/9Ty2SeM.jpg

Broad sheared circulation may be open to the south...

No. Plenty of west winds.

[MississippiWx]

Biggest struggle for Harvey will not be shear, it will be trades. Circulation is closed and still classifies as tropical storm and should stay that way. However, it may be difficult to strengthen much until 75W, per usual Caribbean trade issues. Systems need to be strong upon entering the Eastern Caribbean if they want to continue strengthening at a good pace.