ATL: LORENZO - Post-Tropical - Discussion

[Buck]

Already so big. He would basically fill up the entire GOM.

[SouthDadeFish]

It's definitely unusual to see a hurricane as large and powerful as Lorenzo so far east in the Atlantic. The Atlantic is saying 40W is the new 80W haha

[SconnieCane]

Already so big. He would basically fill up the entire GOM.

Kinda like Katrina at peak, or Ike.

[wxman57]

Take a close-up look at Lorenzo's eye. Looks like it's in the middle of an eyewall replacement cycle. Reminds me of Ike after crossing western Cuba and emerging into the Gulf.

[hurricanes1234]

Truly a beautiful storm

The latest visible images are astounding and gorgeous, with the midday sun penetrating that perfect eye and brilliantly reflecting off the sprawling, banding structure that comprises the system.

[SconnieCane]

Take a close-up look at Lorenzo's eye. Looks like it's in the middle of an eyewall replacement cycle. Reminds me of Ike after crossing western Cuba and emerging into the Gulf.

http://wxman57.com/images/Lorenzo.JPG

I don't think Ike ever looked that good post-Cuba. It took almost until TX LF to start to rebuild a proper core, of course it still had the size to be a very effective water pusher.

[supercane4867]

[wxman57]

With more of the cirrus cleared out, I can see 2 mesovortices inside Lorenzo's eye:

[HurricaneAndre2008]

Cat 4 next advisory?

[cycloneye]

...LORENZO BECOMES A CATEGORY 4 HURRICANE...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.4N 40.2W
ABOUT 1055 MI...1695 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...949 MB...28.03 INCHES

[1900hurricane]

I'd probably go for it. 12Z intensity estimate was 110 kt out of respect of SAB's 5.5, but since then the eye has been consistently warm medium grey and the black ring remains unbroken. Looks like a clear cut FT of 6.0/6.0 to me.



*EDIT: they went for it.

[EquusStorm]

Totally understand the need for NHC intensity forecasts to be careful and conservative but surely even the forecasters can't be too shocked. NHC says it's the most impressive hurricane in that area since Gabrielle 1989.

[tolakram]

501
WTNT43 KNHC 261453
TCDAT3

Hurricane Lorenzo Discussion Number 16
NWS National Hurricane Center Miami FL AL132019
1100 AM AST Thu Sep 26 2019

A review of microwave satellite imagery from last night suggests
that Lorenzo underwent an eyewall replacement cycle, with the
outer eyewall becoming predominant around 06Z-09Z. Around that
time, the hurricane started to rapidly intensify, with the eye
becoming much better defined in conventional satellite imagery. Raw
Data-T numbers from both subjective and objective versions of the
Dvorak Technique suggest that the maximum winds have increased to
near 115 kt, which will be the initial intensity for this advisory.
The initial wind radii have been revised based on a recently
received scatterometer overpass.

The initial motion is 295/11. Lorenzo is approaching a developing
break in the subtropical ridge caused by a series of mid-latitude
troughs to the northwest of the hurricane, and the track guidance
models are in excellent agreement that Lorenzo should recurve
through the break during the forecast period. There are no
significant changes to the guidance since the last advisory, and
there are no significant changes to the forecast track either.

Data from the SHIPS model suggest that Lorenzo will be in an area
of maximum potential intensities of 125-135 kt for the next 3-4
days. This suggests that the rapid intensification should end in
the next 6-12 h as the actual intensity approaches those speeds.
Fluctuations in strength due to eyewall replacement cycles are
expected during the 12-36 h period. The global models suggest
that Lorenzo will subsequently interact with an upper-level trough
during recurvature, which should cause a period of increased shear
and some weakening of the cyclone around 48 h. By 120 h, the
hurricane should weaken due to movement over colder water and into
strong shear in the mid-latitude westerlies.

While its exact ranking will be determined later, Lorenzo is one of
the largest and most powerful hurricanes of record for the central
tropical Atlantic, with the only comparable hurricane in recent
times near there being Gabrielle of 1989.


FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 15.4N 40.2W 115 KT 130 MPH
12H 27/0000Z 16.7N 41.4W 125 KT 145 MPH
24H 27/1200Z 18.5N 42.6W 125 KT 145 MPH
36H 28/0000Z 20.2N 43.5W 120 KT 140 MPH
48H 28/1200Z 21.9N 43.9W 110 KT 125 MPH
72H 29/1200Z 25.2N 43.3W 100 KT 115 MPH
96H 30/1200Z 29.0N 41.0W 100 KT 115 MPH
120H 01/1200Z 34.0N 37.0W 90 KT 105 MPH

$$
Forecaster Beven

[HurricaneRyan]

Totally understand the need for NHC intensity forecasts to be careful and conservative but surely even the forecasters can't be too shocked. NHC says it's the most impressive hurricane in that area since Gabrielle 1989.

Good comparison. This also reminds me a little of Helene 1988.

[Kazmit]

It's interesting how the hurricane-force wind field is only 45 miles while the TS-force wind field is 255 miles.

[DioBrando]

p e r f e c t i o n

[EquusStorm]

While Julia in 2010 was further east as a category four briefly, on Lorenzo's forecast track it'll be slightly outside the confines of any known historical category fours as most were traveling WNW and slightly further west. Jumping on the Irma, Ophelia and Florence train again this year for things happening further NE than they typically should.

[1900hurricane]

You know a system is strong when it looks good on ATMS imagery.

[KWT]

Very impressive hurricane for its location, does look more like something you'd expect at say 20n 60w rather than that far east.

I'd be worried the Azores may get walloped in a similar fashion to how Humberto smashed into Bermuda.

[CrazyC83]

The cloud tops are clearly cooling, but there is still a bit of dry air trying to work in to the north. Solid white ring wraps 3/4 around the storm.