ATL: LORENZO - Post-Tropical - Discussion

[Highteeld]

Dorian

2019SEP01 155019 6.4 935.9 124.6 6.4 6.5 6.5 NO LIMIT OFF OFF OFF OFF 21.47 -68.05 EYE 21 IR 74.4 26.58 76.87 ARCHER GOES16 31.1

[1900hurricane]

We got an AMSU estimate at 2138Z from NOAA-15. The estimate is good for 120 kt/939 mb, which seems consistent with the NHC's intensity estimates from 18Z and 00Z. Still think I would have bumped to 130 kt at 03Z.

CIMSS/NESDIS-USAF/NRL AMSU TC Intensity Estimation:
HURRICANE LORENZO
Thursday 26sep19 Time: 2138 UTC
Latitude: 16.37 Longitude: -40.78
Storm position corresponds to AMSU-A FOV 18 [1<--->30]
-----------------------------------------------------------------
| Estimated MSLP: 939 hPa
| Estimated Maximum Sustained Wind: 120 kts
| Estimate Confidence: Good ( +/- 10mb +/- 12kts )
-----------------------------------------------------------------
Storm is sub-sampled: Bias correction applied is -6.0 hPa
Channel 8 (~150 hPa) Tb Anomaly: 4.36
Channel 7 (~250 hPa) Tb Anomaly: 4.49
Channel 6 (~350 hPa) Tb Anomaly: 4.12
RMW: 18 km
RMW Source is: MW
Environmental Pressure: 1012 (TPC)
Satellite: NOAA-15
ATCF data for Month: 09 Day: 27 Time (UTC): 0000

For imagery, go to http://amsu.ssec.wisc.edu
For all comments and questions mailto:chrisv@ssec.wisc.edu

[EquusStorm]

57.7W for Irma is the easternmost category five on record so that would obliterate the record by a massive amount if it WERE to be classified a 5. Which, I doubt happens without recon support. Cloud tops definitely more impressive than Dorian, but Dorian's symmetry was incredible and though Lorenzo is definitely breaking some records I'd like to see that eyewall organization trend continue before I'd make a case for cat 5. If it somehow goes without an ERC tomorrow it'll be on its way if the OHC there is even enough to support 135-140kt. No doubt the closest candidate in the satellite era in that area though.

[CrazyC83]

Seeing a large area of CMG, borderline CDG, on the southern side, but the cloud tops have warmed a tad on the northern side. If everything can wrap around though, we'd have a solid cat 5.

[1900hurricane]

57.7W for Irma is the easternmost category five on record so that would obliterate the record by a massive amount if it WERE to be classified a 5. Which, I doubt happens without recon support. Cloud tops definitely more impressive than Dorian, but Dorian's symmetry was incredible and though Lorenzo is definitely breaking some records I'd like to see that eyewall organization trend continue before I'd make a case for cat 5. If it somehow goes without an ERC tomorrow it'll be on its way if the OHC there is even enough to support 135-140kt. No doubt the closest candidate in the satellite era in that area though.

Not quite actually. Hugo '89 and Isabel '03 were both a little further to the east as category 5s. Here's all category 5 points east of 60ºW in best track.



Yes, the title says 60ºE. Ignore it, I messed it up.

[EquusStorm]

Hah, I THOUGHT Hugo seemed like it was further east. I must have been thinking about it being the easternmost outside of the deep MDR northeast of the Antilles... but Isabel has it beat there as well. Oops.

[CrazyC83]

 https://twitter.com/CC_StormWatch/status/1177420836548034560

[aperson]

and in rolls the IR frame that says to me "ok that's a cat 5"

[wx98]

https://twitter.com/CC_StormWatch/status/1177420836548034560

Nemo and Dory were in the Pacific but I’m sure Moby Dick is out there wandering around

[CrazyC83]

and in rolls the IR frame that says to me "ok that's a cat 5"

https://cdn.discordapp.com/attachments/625398299092058136/626983357796057088/goes16_ir-dvorak_13L_201909270315.png

I doubt NHC will upgrade on a TC Update or Special Advisory unless it is crystal clear though. Just need the NW quad to thicken about 0.2 degrees for a clear-cut T7.0 (really more like T7.3 in that situation).

[CrazyC83]

There was an instantaneous T7.0 by one version of the ADT:

2019SEP27 014000 6.8 929.4 134.8 6.8 7.0 7.0 NO LIMIT OFF OFF 14.84 -73.07 EYE 25 IR 54.1 17.23 41.32 COMBO

[1900hurricane]

 https://twitter.com/1900hurricane/status/1177439988180553728

[Shell Mound]

Seeing a large area of CMG, borderline CDG, on the southern side, but the cloud tops have warmed a tad on the northern side. If everything can wrap around though, we'd have a solid cat 5.

If I recall correctly, MICHAEL featured a similar convective pattern in its CDO as it rapidly intensified upon landfall in the FL Panhandle. IGOR (2010) also exhibited a similar CDO and peak temperature in the eye at its peak over the open Atlantic. Based on these data, I would say that LORENZO likely peaked at 130-135 knots, though it could have briefly attained Cat-5 status (140 knots). Perhaps the post-seasonal analysis will increase the intensity to at least 130 knots, based on satellite data.

[wx98]

Seeing a large area of CMG, borderline CDG, on the southern side, but the cloud tops have warmed a tad on the northern side. If everything can wrap around though, we'd have a solid cat 5.

If I recall correctly, MICHAEL featured a similar convective pattern in its CDO as it rapidly intensified upon landfall in the FL Panhandle. IGOR (2010) also exhibited a similar CDO and peak temperature in the eye at its peak over the open Atlantic. Based on these data, I would say that LORENZO likely peaked at 130-135 knots, though it could have briefly attained Cat-5 status (140 knots). Perhaps the post-seasonal analysis will increase the intensity to at least 130 knots, based on satellite data.

Why are you saying it’s already peaked?

[wx98]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 27 SEP 2019 Time : 042024 UTC
Lat : 17:49:11 N Lon : 41:33:36 W


CI# /Pressure/ Vmax
6.7 / 929.8mb/132.2kt


Final T# Adj T# Raw T#
6.7 6.7 6.7

Estimated radius of max. wind based on IR : 24 km

Center Temp : +16.5C Cloud Region Temp : -70.6C

Scene Type : EYE

Subtropical Adjustment : OFF

Extratropical Adjustment : OFF

Positioning Method : ARCHER POSITIONING

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 155nmi
- Environmental MSLP : 1012mb

Satellite Name : GOES16
Satellite Viewing Angle : 43.5 degrees

[Shell Mound]

Seeing a large area of CMG, borderline CDG, on the southern side, but the cloud tops have warmed a tad on the northern side. If everything can wrap around though, we'd have a solid cat 5.

If I recall correctly, MICHAEL featured a similar convective pattern in its CDO as it rapidly intensified upon landfall in the FL Panhandle. IGOR (2010) also exhibited a similar CDO and peak temperature in the eye at its peak over the open Atlantic. Based on these data, I would say that LORENZO likely peaked at 130-135 knots, though it could have briefly attained Cat-5 status (140 knots). Perhaps the post-seasonal analysis will increase the intensity to at least 130 knots, based on satellite data.

Why are you saying it’s already peaked?

Stronger westerlies are already impinging on the northwestern semicircle, so LORENZO should begin to slowly weaken within a day, despite warming SSTs.

[Stormi]

It appears sheared to the WNW to me...could be wrong as I'm a newbie. Other areas look stronger though to me

[NotSparta]

Making a move to the N, may be a wobble though

[FireRat]

Wow, Lorenzo is looking pretty powerful! Sure, it might not get classified as Category 5 unless it's CDO gets even more symmetric and the eye more round. I think Igor 2010 is a good comparison.
Also, this storm may be a case like Edouard 1996, which was kept as Cat 4 even though he looked like a 5 to me at its peak. With no recon, it is hard to get a 5 far east in this basin lol.

[Yellow Evan]

and in rolls the IR frame that says to me "ok that's a cat 5"

https://cdn.discordapp.com/attachments/625398299092058136/626983357796057088/goes16_ir-dvorak_13L_201909270315.png

That frame might not even qualify as T6.5.

This is basically an EPAC esque strong Cat 4.