WPAC: BOLAVEN - Post-Tropical

[doomhaMwx]

 https://twitter.com/sayakasofiamori/status/1712217024477437971

[qscdefb]

https://i.imgur.com/upcu0SV.png
bullseye pass

I checked the 500m data, and it’s clear that the wind speeds are artificially capped at 80.0 m/s, so there is a low bias.

[mrbagyo]

The eyewall is still thick and intense on the last 2 microwaves

[doomhaMwx]

It did look like concentric eyewalls were present on microwave data at ~16Z, particularly on 37 GHz frequency which scans the low levels, but it's incredible how we still have yet to see an EWRC actually happen.

(FY-3D MWRI images courtesy of Dapiya)

[doomhaMwx]

Latest microwave scan finally shows a legit EWRC, and cloud tops around the eye have significantly warmed up as a result.

[Ptarmigan]

Looks stronger than 900 millibars.

[doomhaMwx]

15W BOLAVEN 231012 0000 20.6N 143.0E WPAC 150 908

[mrbagyo]

15W BOLAVEN 231012 0600 21.8N 143.5E WPAC 155 905

They'll probably revise this

[doomhaMwx]

Interesting that JTWC bumped up the intensity back to 155kts after giving 150kts at 00Z, especially now that the system is in the midst of an EWRC.

15W BOLAVEN 231012 0600 21.8N 143.5E WPAC 155 905
15W BOLAVEN 231012 0000 20.6N 143.0E WPAC 150 908
15W BOLAVEN 231011 1800 19.7N 142.9E WPAC 155 903

Huh, JTWC in its 09Z prognostic reasoning says that EWRC has been completed. That ~06Z MW image definitely says otherwise.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM
HAS COMPLETED AN EYEWALL REPLACEMENT AND HAS RE-INTENSIFIED IN THE
LAST FEW HOURS, SPORTING A NEW SHARPLY-OUTLINED 13-NM EYE. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE IN
THE EIR LOOP AND SPOT ON WITH A MICROWAVE EYE FEATURE IN THE
120613Z SSMIS 37GHZ IMAGE. THE INITIAL INTENSITY OF 155KTS IS ALSO
PLACED WITH HIGH CONFIDENCE BASED ON THE DVORAK ESTIMATES FROM
PGTW, KNES, AND RJTD AND REFLECTS THE 6-HR IMPROVEMENT.

[aspen]

Bolaven’s persistence is quite impressive. It’s been holding on to a fantastic structure for so long despite an EWRC trying to start for the last 12+ hours. I would’ve expected the eye to have collapsed by now.

I think this could’ve hit 160 kt. That 8z SAR pass from yesterday found 155 kt at its 300m resolution, so assuming there could’ve been some undersampling, 160 kt seems possible, especially when Bolaven’s eye hit 26C. Maybe 165 kt is possible. However, I think 155 kt is a fair estimate based on Dvorak (once it finally caught up) and the SAR pass. The pressure was probably deep into the 890s.

[mrbagyo]

Wow, It's still at 155 knots / 905 hPa at 12z

15W BOLAVEN 231012 1200 22.6N 144.3E WPAC 155 905

[mrbagyo]

Fresh microwave still shows a very intense inner core.
looks like a gigantic Fibonacci spiral

[doomhaMwx]

SAR pass at ~08Z found 155kts.

[Sciencerocks]

 https://twitter.com/CIRA_CSU/status/1712495679195558159

[Hayabusa]

169 kts from AMSU @ 1012/11z

[Hayabusa]

This has to be the lowest init yet since HFSA began operations. 853 and 855 mb

[qscdefb]

SAR pass at ~08Z found 155kts.

https://www.star.nesdis.noaa.gov/socd/mecb/sar/AKDEMO_products/APL_winds/tropical/2023/WP152023_BOLAVEN/RSAT2_GSS_2023_10_12_08_37_37_0750415057_141.85E_21.01N_VH_C-11_MERGED02_RadialWinds_4Quads_3.0km.png
https://www.star.nesdis.noaa.gov/socd/mecb/sar/AKDEMO_products/APL_winds/tropical/2023/WP152023_BOLAVEN/RSAT2_GSS_2023_10_12_08_37_37_0750415057_141.85E_21.01N_VH_C-11_MERGED02_wind.png

It took me 5 seconds to realise it’s 08Z of the 12th, not the 11th lol, Bolaven has maintained its intensity too well

[doomhaMwx]

Downgraded below category 5 for the first time in two days.

15W BOLAVEN 231013 0000 25.4N 146.9E WPAC 130 923

T2315(Bolaven)
Issued at 2023/10/13 00:50 UTC

Analysis at 10/13 00 UTC
Grade TY
Scale Large
Intensity Violent
Center position N25°25′ (25.4°)
E146°55′ (146.9°)
Direction and speed of movement NE 35 km/h (20 kt)
Central pressure 915 hPa
Maximum sustained wind speed near center 55 m/s (105 kt)
Maximum wind gust speed 75 m/s (150 kt)
Radius of 50-kt wind area 200 km (110 NM)
Radius of 30-kt wind area E560 km (300 NM)
W440 km (240 NM)

[Foxfires]

So.. EWRC or no? latest microwave passes don't exactly look EWRC-y anymore but I'm no expert.

[StormTracker89]

It did look like concentric eyewalls were present on microwave data at ~16Z, particularly on 37 GHz frequency which scans the low levels, but it's incredible how we still have yet to see an EWRC actually happen.

(FY-3D MWRI images courtesy of Dapiya)

https://i.imgur.com/tfNXtrM.png
https://i.imgur.com/kjyW57g.png

Are these FY-3D MWRI images posted anywhere publicly available?