ATL: LESLIE - Remnants - Discussion

[underthwx]

https://i.imgur.com/iC2ACAl.png

Probably around 95 kt in reality, my posts are opinion only, etc.

Leslie looks like a pretty formidable cyclone....I haven't paid much attention to it.....will this become stronger?...

[weeniepatrol]

[Teban54]

Looking like Lingering Leslie won't let her time up just yet...

Just like her 2018 self:

[MEANINGLESS_NUMBERS]

This is the best looking storm in the Atlantic basin right now.

[AnnularCane]

I believe Leslie 2012 hung around for a while too.

I'm seeing a pattern here.

[weeniepatrol]

SAB came in at T5.5, NHC will probably go 85 kt next advisory.

[Travorum]

SAR winds aren't quite up to where they were at the first peak but given Leslie's rapidly improving appearance I expect they will catch up in short time.

First peak 10-06 21z:	Most recent pass 10-09 21z:
Platform: RCM-3 Acquisition Date: 2024-10-06 20:35:21 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -38.723 Storm Center Latitude: 14.188 Incidence Angle (Degrees): 21.348 Quadrant 1 NE VMax (kts): 106.01 Quadrant 2 SE VMax (kts): 79.80 Quadrant 3 SW VMax (kts): 95.53 Quadrant 4 NW VMax (kts): 104.07 RMax (nmi): 7.00 - 9.00	Platform: RCM-2 Acquisition Date: 2024-10-09 21:33:37 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -49.032 Storm Center Latitude: 22.078 Incidence Angle (Degrees): 56.170 Quadrant 1 NE VMax (kts): 93.08 Quadrant 2 SE VMax (kts): 84.88 Quadrant 3 SW VMax (kts): 82.06 Quadrant 4 NW VMax (kts): 91.58 RMax (nmi): 7.00 - 8.00

[cycloneye]

Cat 2!!!!. She is a fighter.

AL, 13, 2024101000, , BEST, 0, 223N, 490W, 90, 972, HU

[Teban54]

C'mon Leslie, you're only 10 kts away from boosting this season's MH totals! We have faith in you!

[aspen]

SAR winds aren't quite up to where they were at the first peak but given Leslie's rapidly improving appearance I expect they will catch up in short time.

First peak 10-06 21z:	Most recent pass 10-09 21z:
https://i.imgur.com/tERW6al.png	https://i.imgur.com/ic7bAYk.png
Platform: RCM-3 Acquisition Date: 2024-10-06 20:35:21 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -38.723 Storm Center Latitude: 14.188 Incidence Angle (Degrees): 21.348 Quadrant 1 NE VMax (kts): 106.01 Quadrant 2 SE VMax (kts): 79.80 Quadrant 3 SW VMax (kts): 95.53 Quadrant 4 NW VMax (kts): 104.07 RMax (nmi): 7.00 - 9.00	Platform: RCM-2 Acquisition Date: 2024-10-09 21:33:37 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -49.032 Storm Center Latitude: 22.078 Incidence Angle (Degrees): 56.170 Quadrant 1 NE VMax (kts): 93.08 Quadrant 2 SE VMax (kts): 84.88 Quadrant 3 SW VMax (kts): 82.06 Quadrant 4 NW VMax (kts): 91.58 RMax (nmi): 7.00 - 8.00

Wow 105 kt from the first peak. So I guess it was significantly under-estimated; I thought 80 kt was reasonable since Leslie’s best structure was so brief.

[Teban54]

SAR winds aren't quite up to where they were at the first peak but given Leslie's rapidly improving appearance I expect they will catch up in short time.

First peak 10-06 21z:	Most recent pass 10-09 21z:
https://i.imgur.com/tERW6al.png	https://i.imgur.com/ic7bAYk.png
Platform: RCM-3 Acquisition Date: 2024-10-06 20:35:21 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -38.723 Storm Center Latitude: 14.188 Incidence Angle (Degrees): 21.348 Quadrant 1 NE VMax (kts): 106.01 Quadrant 2 SE VMax (kts): 79.80 Quadrant 3 SW VMax (kts): 95.53 Quadrant 4 NW VMax (kts): 104.07 RMax (nmi): 7.00 - 9.00	Platform: RCM-2 Acquisition Date: 2024-10-09 21:33:37 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -49.032 Storm Center Latitude: 22.078 Incidence Angle (Degrees): 56.170 Quadrant 1 NE VMax (kts): 93.08 Quadrant 2 SE VMax (kts): 84.88 Quadrant 3 SW VMax (kts): 82.06 Quadrant 4 NW VMax (kts): 91.58 RMax (nmi): 7.00 - 8.00

Wow 105 kt from the first peak. So I guess it was significantly under-estimated; I thought 80 kt was reasonable since Leslie’s best structure was so brief.

Keep in mind, SAR was showing Jose as a hurricane last year and it wasn't upgrade in TCR. I believe there were other such instances in the last two years, too. I don't think NHC treats it as a reliable tool yet, which means I also don't know how reliable it is.

[aspen]

SAR winds aren't quite up to where they were at the first peak but given Leslie's rapidly improving appearance I expect they will catch up in short time.

First peak 10-06 21z:	Most recent pass 10-09 21z:
https://i.imgur.com/tERW6al.png	https://i.imgur.com/ic7bAYk.png
Platform: RCM-3 Acquisition Date: 2024-10-06 20:35:21 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -38.723 Storm Center Latitude: 14.188 Incidence Angle (Degrees): 21.348 Quadrant 1 NE VMax (kts): 106.01 Quadrant 2 SE VMax (kts): 79.80 Quadrant 3 SW VMax (kts): 95.53 Quadrant 4 NW VMax (kts): 104.07 RMax (nmi): 7.00 - 9.00	Platform: RCM-2 Acquisition Date: 2024-10-09 21:33:37 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -49.032 Storm Center Latitude: 22.078 Incidence Angle (Degrees): 56.170 Quadrant 1 NE VMax (kts): 93.08 Quadrant 2 SE VMax (kts): 84.88 Quadrant 3 SW VMax (kts): 82.06 Quadrant 4 NW VMax (kts): 91.58 RMax (nmi): 7.00 - 8.00

Wow 105 kt from the first peak. So I guess it was significantly under-estimated; I thought 80 kt was reasonable since Leslie’s best structure was so brief.

Keep in mind, SAR was showing Jose as a hurricane last year and it wasn't upgrade in TCR. I believe there were other such instances in the last two years, too. I don't think NHC treats it as a reliable tool yet, which means I also don't know how reliable it is.

Do we have any instances of storms with simultaneous recon and SAR data to judge its accuracy?

Also I thought SAR was used by the NHC at least once before but I forget the context. Maybe I’m mistaken.

[cycloneye]

[Travorum]

SAR winds aren't quite up to where they were at the first peak but given Leslie's rapidly improving appearance I expect they will catch up in short time.

First peak 10-06 21z:	Most recent pass 10-09 21z:
https://i.imgur.com/tERW6al.png	https://i.imgur.com/ic7bAYk.png
Platform: RCM-3 Acquisition Date: 2024-10-06 20:35:21 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -38.723 Storm Center Latitude: 14.188 Incidence Angle (Degrees): 21.348 Quadrant 1 NE VMax (kts): 106.01 Quadrant 2 SE VMax (kts): 79.80 Quadrant 3 SW VMax (kts): 95.53 Quadrant 4 NW VMax (kts): 104.07 RMax (nmi): 7.00 - 9.00	Platform: RCM-2 Acquisition Date: 2024-10-09 21:33:37 UTC Storm Name: AL132024 / LESLIE Storm ID: AL13 Storm Center Longitude: -49.032 Storm Center Latitude: 22.078 Incidence Angle (Degrees): 56.170 Quadrant 1 NE VMax (kts): 93.08 Quadrant 2 SE VMax (kts): 84.88 Quadrant 3 SW VMax (kts): 82.06 Quadrant 4 NW VMax (kts): 91.58 RMax (nmi): 7.00 - 8.00

Wow 105 kt from the first peak. So I guess it was significantly under-estimated; I thought 80 kt was reasonable since Leslie’s best structure was so brief.

Keep in mind, SAR was showing Jose as a hurricane last year and it wasn't upgrade in TCR. I believe there were other such instances in the last two years, too. I don't think NHC treats it as a reliable tool yet, which means I also don't know how reliable it is.

Yes, SAR is neither reliable enough nor tested enough to be used operationally and as such NHC does not use it to operationally assess intensity, from what it sounds like they may not even use it as evidence for changes in TSRs. It is a microwave wind speed estimation tool similar to ASCAT or SFMR and as such is subject to similar biases in the brightness temp to wind speed algorithm (It's actually similar to an ASCAT sensor that points at a specific point over a longer time to capture data at a higher resolution, 500m vs 25km). The geophysical model functions they use to relate the microwave backscatter to wind speeds are actively being changed and improved and a specific geophysical model function is used for each satellite. All this to say it's definitely not developed enough to be used operationally but is an interesting bit of data to look at nonetheless.

You can read more about the technical specifications of SAR wind measurement here: https://www.star.nesdis.noaa.gov/socd/m ... ch_doc.php

[Travorum]

Wow 105 kt from the first peak. So I guess it was significantly under-estimated; I thought 80 kt was reasonable since Leslie’s best structure was so brief.

Keep in mind, SAR was showing Jose as a hurricane last year and it wasn't upgrade in TCR. I believe there were other such instances in the last two years, too. I don't think NHC treats it as a reliable tool yet, which means I also don't know how reliable it is.

Do we have any instances of storms with simultaneous recon and SAR data to judge its accuracy?

Also I thought SAR was used by the NHC at least once before but I forget the context. Maybe I’m mistaken.

Apparently recon data is one source they use to calibrate the SAR geophysical model functions so I'm sure there are cases that could easily be found if anyone put in the time to synchronize recon data to SAR passes.

[aspen]

https://i.imgur.com/HdNbFyh.gif

I think 90 kt is a pretty good estimate for this. The eye isn’t clear enough to confidently say it’s a low-end major.

[Teban54]

Eye clearing out:

[cycloneye]

YES!!!!! Forecast to be a major.

FORECAST VALID 10/1200Z 23.3N 49.9W
MAX WIND 100 KT...GUSTS 120 KT.

[HurricaneAndre2008]

TXNT24 KNES 100025
TCSNTL

A. 13L (LESLIE)

B. 10/0000Z

C. 22.3N

D. 49.0W

E. ONE/GOES-E

F. T5.5/5.5

G. IR/EIR/SWIR

H. REMARKS...EYE PATTERN WITH A MG EYE SURROUNDED BY W AND EMBEDDED IN
B YIELDING A DT=5.5 INCLUDING 0.0 ADJUSTMENT. MET=5.0. PT=5.5. THE FT
IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...LEE

[weeniepatrol]

...LESLIE NOW A CATEGORY 2 HURRICANE AND COULD MAKE A RUN AT MAJOR HURRICANE INTENSITY...