MPI (maximun potential index) which is essentially the thermodynamic upper limit of the TC.

MPI is slightly lower than it was last night although still supports a bottom level Cat5. Over the next 24 hours MPI will increase once again. If shear stays low, then EWRC depending there is nothing theoretically stopping the cyclone from undergoing RI for a third time although it is unlikely because everytime there is a EWRC the cyclone grows bigger. Its easier to maintain a smaller cat5 than a mamoth sized one.

Lorenzo to hit the NW Azores on Tue/Wed; the islands generally are now on watch or warning. Its fate when it gets o the UK is still uncertain - see model output.

Quo Vadis:

https://www.forbes.com/sites/marshallshepherd/2019/09/29/hurricane-lorenzo-is-too-strong-for-where-it-islets-deal-with-the-climate-change-question/

"Hurricane Lorenzo rapidly strengthened into a scale-topping category five hurricane on Saturday evening, with maximum sustained winds reaching an incredible 160 MPH. This breaks the record for both the easternmost and northernmost category five hurricane ever recorded in the Atlantic Ocean "

NOAA now has Lorenzo brushing past the west of Ireland, so that must be the more favoured route now:

https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/053355.shtml?tswind120#contents

Quo Vadis:

https://www.forbes.com/sites/marshallshepherd/2019/09/29/hurricane-lorenzo-is-too-strong-for-where-it-islets-deal-with-the-climate-change-question/

"Hurricane Lorenzo rapidly strengthened into a scale-topping category five hurricane on Saturday evening, with maximum sustained winds reaching an incredible 160 MPH. This breaks the record for both the easternmost and northernmost category five hurricane ever recorded in the Atlantic Ocean "

NOAA now has Lorenzo brushing past the west of Ireland, so that must be the more favoured route now:

https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/053355.shtml?tswind120#contents

 

I suspect the guidance has been influenced by the ECM 00z output which now shows a similar scenario https://www.wetterzentrale.de/maps/ECMOPEU00_96_1.png 

 

I suspect the guidance has been influenced by the ECM 00z output which now shows a similar scenario https://www.wetterzentrale.de/maps/ECMOPEU00_96_1.png 

As was highlighted on the Countryfile programme last night the behaviour was dependent on the interaction or otherwise with the jet stream.  Something between the two sharply different scenarios (filling low near Biscay or deep low near Iceland) was said to be probable.

Hopefully the Azores won’t be badly impacted.

Lorenzo seems to be getting its act together this evening after more than a day of steady weakening since its cat5 status. Eye starting to clear out and the dry slots are filling, everything looks more symmetrical.

One other thing. Lorenzo is huge. Much more typhoon like than atlantic hurricane.

A gale diameter of nearly 500 miles, its cloud shield is something like 1500 miles.

OK pretty sure its RI for the third time.

So we may get an upgrade to a cat3

Now vs 5 hours ago. Eye very rapidally clearing. Convection becoming symmetric.

High level cloud from lorenzo has reached the Azores despite the centre still being over 1000km away.

Yes, he is a big boy! 

https://www.ssd.noaa.gov/PS/TROP/storms/MITAG.html

Shanghai in the firing line and later Japan

Lorenzo still giving the models problems - after yesterday giving it a clear run to Iceland, today shows storm force winds late on Thursday for Northern Ireland and the Western Isles.

Some BIG wave heights - graphic here

https://twitter.com/i/status/1178656839501860864

Entire GEFS suite has switched to Lorenzo impacting West Coast EIRE and NI, then sliding across the UK

Looks like Lorenzo will track just far east enough that it's warm core is only partially eroded from the west as it moves near or over Ireland then Scotland. 

There may be at least half of an eyewall structure in place during that time - albeit not one of hurricane intensity, unless the models & official guidance are underestimating the system considerably, which would be a bit of a calamity. Seems unlikely, but given just how large Lorenzo is, who knows, maybe it'll wind down more slowly than generally expected?

Just a thought, not a forecast!

The latest fax chart has Lorenzo on a more southerly track once more and heading straight for the RoI and then the UK.

But by the time it reaches us it is a vastly weakened system however.

The latest fax chart has Lorenzo on a more southerly track once more and heading straight for the RoI and then the UK.

But by the time it reaches us it is a vastly weakened system however.

Maybe not that much weakened. It's the first time that I can remember that shows an ex-hurricane still well organised enough to feature as a storm on NHC charts (39-73 mph sustained winds) over southern England - just south of The Wash.

https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/055036.shtml?cone#contents - on Friday

Direct hit forecast this morning: