Hurricane Irma

[crimsone]

1 minute ago, Iceberg said:

Vortex confirms a closed eye. Pressure 10mb less than the nhc estimate only an hr ago. 

*wonders how wide the eye is*

This is... err... worrying... and utterly fascinating.

[Yarmy]

To my slightly dodgy eyes, the GFS 06z has sent her still further south and west. GEFS will be interesting (if that's the right word) later.

[karyo]

28 minutes ago, Yarmy said:

To my slightly dodgy eyes, the GFS 06z has sent her still further south and west. GEFS will be interesting (if that's the right word) later.

Yes, that's how I see it too. Practically entering the Golf. Then going north through Florida.

Edited September 4, 2017 by karyo

[Iceberg]

Recon find her still getting stronger now 946mb. A run at cat 4 today. 

Just checked raw Dvorak as she is 6.4 which is a strong cat 4. 

She looks incredibly good on sat. 

Might take a few hrs for winds to respond.  

[Iceberg]

39 minutes ago, crimsone said:

*wonders how wide the eye is*

This is... err... worrying... and utterly fascinating.

Eye is circular at 18 miles. 

Tropical winds extend to the edge of the cdo, near enough. 

[crimsone]

I should probably look up how to read a VDM again. I think the last time I read one was for Wilma lol.

[crimsone]

Kinda beautiful, and also a bit threatening. Rather puts this thing in perspective...

https://weather.us/satellite/572-w-160-n/satellite-water-vapor-15min.html#play

[crimsone]

 

Edited September 4, 2017 by crimsone

[Summer Sun]

 

[crimsone]

Pressure down to 948 mb on recon's second pass.

"EYEWALL WEAKER NW THROUGH NE", they say... which presumably means the whole northern side.

[Yarmy]

 

[Iceberg]

Apart from that comment I. Can't really find much evidence of an erc. 

The 1min sliders seem to show a pretty stable eye. 

The gfs 06z shooting Irma through Florida seems a little unbelievable. Keeping it at a cat 4 with hurricane winds for 95% of Florida might be over the top. It also puts almost the  bottom half of Florida in 100kt winds. 

[crimsone]

Venezuela looks like it's trying to feel like it's somehow involved here, forecasting a 10% chance of Irma ignoring all steering forces and just barrelling onward from its current location in a straight line 
 

 

Edited September 4, 2017 by crimsone

[stodge]

5 minutes ago, Iceberg said:

The gfs 06z shooting Irma through Florida seems a little unbelievable. Keeping it at a cat 4 with hurricane winds for 95% of Florida might be over the top. It also puts almost the  bottom half of Florida in 100kt winds. 

Except that it now mirrors the 00Z GEM:

The 00Z ECM slightly further east but the track has veered noticeably west in the past 24 hours with the recurving starting to the south of Florida so the storm moves from north to south either along the Gulf coast, the Atlantic coast or straight through the middle of the state.

The Carolinas and the mid-Atlantic states seem to have been spared a hit at this time but you have to wonder IF further westerly movement will bring Irma back into the Gulf of Mexico with all that could follow.

[Yarmy]

Eyeballing the GEFS perturbations, I'd say only about 3 of the 20 miss Florida to the east. The majority head straight through with a few further W into the Gulf. It's not looking good.

[weatherobsuk]

The past windyty model-runs have taken Irma following the Dominican Republic-Cuba northern coastline aiming the core just offshore Miami, with each run the trend has gone westwards taking Irma closer inland to Florida.

[stodge]

23 minutes ago, Yarmy said:

Eyeballing the GEFS perturbations, I'd say only about 3 of the 20 miss Florida to the east. The majority head straight through with a few further W into the Gulf. It's not looking good.

Indeed and further westward corrections could mean a glancing blow for Florida and a direct hit on Louisiana with the storm having further time to strengthen.

[crimsone]

1 minute ago, stodge said:

Indeed and further westward corrections could mean a glancing blow for Florida and a direct hit on Louisiana with the storm having further time to strengthen.

Can't say that that's impossible, because it's not. On the current information though, it seems quite unlikely. If it happens, I'll eat my imaginary hat.

[crimsone]

I'm not convinced. Going by the eye, that's approximately one degree of latitude in about 10 hours.

 

[crimsone]

So, this graphic, though posted yesterday, was actually initialised about 49 hours ago... so pretty out of date.

Nevertheless, it seems to provide a pretty good explanation of what the hell's going on and why.
 

 

Edited September 4, 2017 by crimsone

[crimsone]

So, the latest recon (I make it an hour ago - 1142z) seems to be reporting an open eye (ie, not at least 50% surrounded by cloud), and the beginnings of eyewall replacement, with concentric eyewalls at 15 and 30 miles.

Pressure pretty steady at 947mb, which is slightly remarkable considering the above.

 

Edited September 4, 2017 by crimsone

[Summer Sun]

 

[Iceberg]

Yep concentric 15-30  so an erc it is. On sat it's difficult to see but I'd imagine wall replacement happens pretty smoothly. 

Dvorak is still above 6 indicating a cat 4 pressure hints at a cat 4 as well with nhc officially upgrading to 947mb. 

Winds need to respond now. 

The ease and frequency of an erc for Irma seems to indicate  more fragile walls so potentially weaker wall structure. 

Hopefully a strong wall never appears as sometimes happens with canes. However if a strong wall happens then we could see a massive and quick drop in pressure down to the 920s. 

[crimsone]

Interestingly, 06z HWRF now has this thing getting almost completely smashed up over Cuba and emerging on the south side. Seems to be an outlier, but an interesting one even so.

 

[karyo]

8 minutes ago, crimsone said:

Interestingly, 06z HWRF now has this thing getting almost completely smashed up over Cuba and emerging on the south side. Seems to be an outlier, but an interesting one even so.

 

Wow! Let's see whether the 12z's will bring any further shift west. I haven't been so interested in what the models show since winter!