ATL: IRMA - Post-Tropical - Discussion

[TheStormExpert]

 https://twitter.com/mjventrice/status/903315637241556992

[TheStormExpert]

Yikes, Cat 5 towards NE Caribbean... Cat 3 moving towards SFL... Ugh...

Well he did get the major hurricane drought ending right so who knows. Hopefully he is being over-bullish as usual but he has been worried about in-close action since early spring.

[RL3AO]

Unfortunately a cat 4/5 near the Leewards/Puerto Rico is becoming less of a potential and more of a likelihood. Still has time to shift some, but its never too soon to start preparing.

[Gustywind]

Unfortunately a cat 4/5 near the Leewards/Puerto Rico is becoming less of a potential and more of a likelihood. Still has time to shift some, but its never too soon to start preparing.

So you think that a cat 4 / 5 CANE is highly possible close to the Leewards?

[gatorcane]

nice looking hurricane and gaining some latitude like the models have forecasted:

[cycloneye]

Unfortunately a cat 4/5 near the Leewards/Puerto Rico is becoming less of a potential and more of a likelihood. Still has time to shift some, but its never too soon to start preparing.

I have been prepared since June 1 but now the plot thikens and more things to do for me and less time in S2K.I really hope it spares PR because the power and water grids are not in the best shape to handle a 4 or 5 or even a cat 1.

[RL3AO]

Unfortunately a cat 4/5 near the Leewards/Puerto Rico is becoming less of a potential and more of a likelihood. Still has time to shift some, but its never too soon to start preparing.

So you think that a cat 4 / 5 CANE is highly possible close to the Leewards?

Im not ready to go "highly likely" yet. A track, especially to the north still possible.

[Ivanhater]

I don't mean to be brash but this is exactly why you should never post season cancel posts and comparing to 2013 in July and early August. We have one of the biggest natural disasters in the U.S from Harvey and now what looks to be another disaster from Irma for the Isands and potentially beyond.....I sincerely hope those who were take a lesson from this.

[Gustywind]

Unfortunately a cat 4/5 near the Leewards/Puerto Rico is becoming less of a potential and more of a likelihood. Still has time to shift some, but its never too soon to start preparing.

I have been prepared since June 1 but now the plot thikens and more things to do for me and less time in S2K.I really hope it spares PR because the power and water grids are not in the best shape to handle a 4 or 5 or even a cat 1.

Luis, the prédictions seem unreall even if we're far away from reality. Hope no that could be a nightmare for us in Guadeloupe and the whole islands chains north of us Antigua Barbuda the Northern Leewards and you too! Let's keep our fingers crossed hoping that this fat LADY will spare us anywhere.

[Gustywind]

Unfortunately a cat 4/5 near the Leewards/Puerto Rico is becoming less of a potential and more of a likelihood. Still has time to shift some, but its never too soon to start preparing.

So you think that a cat 4 / 5 CANE is highly possible close to the Leewards?

Im not ready to go "highly likely" yet. A track, especially to the north still possible.

I prefer that hope that north escape.. come quickly but that's another story not the one of NHC prédictions for the moment. Anyway, i will read you carefully

[Aric Dunn]

I mean overall the models for 12z shifted north even the UKMET. the EURO is the outlier for once..

[cycloneye]

Hurricane Irma Discussion Number 6
NWS National Hurricane Center Miami FL AL112017
500 PM AST Thu Aug 31 2017

Irma has become an impressive hurricane with intense eyewall
convection surrounding a small eye. Satellite estimates continue to
rapidly rise, and the Dvorak classifications from both TAFB & SAB
support an initial wind speed of 100 kt. This is a remarkable 50-kt
increase from yesterday at this time.

Microwave and satellite data suggest that an eyewall replacement
cycle could be starting. This isn't surprising given how small the
eye is, and will probably be the first of many eyewall cycles for
this hurricane. Overall, Irma should be in a low-shear environment
for several days, with the intensity controlled by eyewall cycles
and the moderately warm SSTs along the path. Thus the forecast
intensity is leveled off for the next 2 days. After the weekend,
Irma should be moving over much warmer water, with SSTs forecast to
be 29C at the end of the period. All indications are for Irma to be
strengthening by the end of the forecast period, with the NHC
prediction adjusted slightly upward from the previous one, in line
with the extremely low pressures forecast by the global and regional
hurricane models at that time.

Irma continues moving west-northwestward, now at about 10 kt.
There has been no change to the forecast philosophy, with the
hurricane likely to turn westward and west-southwestward over the
next few days due to a building ridge over the central Atlantic. At
long range, however, model guidance is not in good agreement on the
strength of the ridge, resulting in some significant north-south
differences in the global models. I am inclined to stay on the
southwestern side of the model guidance, given the rather consistent
forecasts of the ECMWF and its ensemble. In addition, the strongest
members of the recent ensembles are on the southern side on the
consensus, giving some confidence in that approach.


FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 17.3N 34.8W 100 KT 115 MPH
12H 01/0600Z 17.8N 36.2W 105 KT 120 MPH
24H 01/1800Z 18.2N 38.3W 105 KT 120 MPH
36H 02/0600Z 18.3N 40.7W 105 KT 120 MPH
48H 02/1800Z 17.9N 42.9W 105 KT 120 MPH
72H 03/1800Z 16.8N 47.5W 110 KT 125 MPH
96H 04/1800Z 16.0N 52.0W 115 KT 130 MPH
120H 05/1800Z 16.5N 56.5W 120 KT 140 MPH

$$
Forecaster Blake

[Snowman67]

When is the last time we had back to back major hurricanes alphabetically (I know Irma is not a major yet)?

[weathernerdguy]

When is the last time we had back to back major hurricanes alphabetically (I know Irma is not a major yet)?

Last year with Matthew and Nicole

[caneseddy]

Hurricane Irma Discussion Number 6
NWS National Hurricane Center Miami FL AL112017
500 PM AST Thu Aug 31 2017

Irma has become an impressive hurricane with intense eyewall
convection surrounding a small eye. Satellite estimates continue to
rapidly rise, and the Dvorak classifications from both TAFB & SAB
support an initial wind speed of 100 kt. This is a remarkable 50-kt
increase from yesterday at this time.

Microwave and satellite data suggest that an eyewall replacement
cycle could be starting. This isn't surprising given how small the
eye is, and will probably be the first of many eyewall cycles for
this hurricane. Overall, Irma should be in a low-shear environment
for several days, with the intensity controlled by eyewall cycles
and the moderately warm SSTs along the path. Thus the forecast
intensity is leveled off for the next 2 days. After the weekend,
Irma should be moving over much warmer water, with SSTs forecast to
be 29C at the end of the period. All indications are for Irma to be
strengthening by the end of the forecast period, with the NHC
prediction adjusted slightly upward from the previous one, in line
with the extremely low pressures forecast by the global and regional
hurricane models at that time.

Irma continues moving west-northwestward, now at about 10 kt.
There has been no change to the forecast philosophy, with the
hurricane likely to turn westward and west-southwestward over the
next few days due to a building ridge over the central Atlantic. At
long range, however, model guidance is not in good agreement on the
strength of the ridge, resulting in some significant north-south
differences in the global models. I am inclined to stay on the
southwestern side of the model guidance, given the rather consistent
forecasts of the ECMWF and its ensemble. In addition, the strongest
members of the recent ensembles are on the southern side on the
consensus, giving some confidence in that approach.


FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 17.3N 34.8W 100 KT 115 MPH
12H 01/0600Z 17.8N 36.2W 105 KT 120 MPH
24H 01/1800Z 18.2N 38.3W 105 KT 120 MPH
36H 02/0600Z 18.3N 40.7W 105 KT 120 MPH
48H 02/1800Z 17.9N 42.9W 105 KT 120 MPH
72H 03/1800Z 16.8N 47.5W 110 KT 125 MPH
96H 04/1800Z 16.0N 52.0W 115 KT 130 MPH
120H 05/1800Z 16.5N 56.5W 120 KT 140 MPH

$$
Forecaster Blake

NHC not buying the GFS runs

[Snowman67]

Man I hope a front comes down and turns it away if it gets close to the U.S. I don't even want to contemplate this thing getting into the central or western GOM.

[tgenius]

At this point I almost don't want to look until Sunday/Monday, At that point we are close to the 5-9 day timeframe and likely will have some GIV data ingested into the model runs.

[WeatherEmperor]

The NHC is showing a lot of respect to the Euro and its ensembles in their 5pm update


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[KWT]

nice looking hurricane and gaining some latitude like the models have forecasted:

It is gaining latitude but nearly as early as the GFS suite of models predicted, which had this at 19N by 34W...in reality its down at 17N still!

NHC are showing the ECM lots of respect, maybe too much? Still it has been VERY consistent with its range, the GFS and its ensembles have flip flopped quite alot recently.

[RL3AO]

Key point from Eric Blake in the discussion.

In addition, the strongest
members of the recent ensembles are on the southern side on the
consensus, giving some confidence in that approach.

This has been a trend for a couple days. The Euro ensembles that have had Irma as cat 4s and 5s have been the southern most tracks in the ensemble.