CPAC: LANE - Post-Tropical

[CrazyC83]

Highest unflagged SFMR winds reported by the NOAA aircraft were 152 knots so far.

Yep, so the guess of 155 knots is probably a good one.

They probably won't go that high since the flight-level winds support much less and there is a known high bias in very intense hurricanes while deepening. The FL winds support about 130 kt. A blend of the data would be 140-145 kt.

[Highteeld]

This is not a category 4 hurricane by any stretch of the imagination right now. Keeping it at cat 4 is a disservice to the public.

[CrazyC83]

This is not a category 4 hurricane by any stretch of the imagination right now. Keeping it at cat 4 is a disservice to the public.

The SFMR does have a known significant high bias, and flight-level winds don't support cat 5 yet. But it is up to CPHC. Pressure looks to be around 924.

[Alyono]

This is not a category 4 hurricane by any stretch of the imagination right now. Keeping it at cat 4 is a disservice to the public.

The SFMR does have a known significant high bias, and flight-level winds don't support cat 5 yet. But it is up to CPHC. Pressure looks to be around 924.

That is a matter of question. HRD scientists who maintain the SFMR do not actually agree with the NHC assessment of the high bias

[BYG Jacob]

This is not a category 4 hurricane by any stretch of the imagination right now. Keeping it at cat 4 is a disservice to the public.

The SFMR does have a known significant high bias, and flight-level winds don't support cat 5 yet. But it is up to CPHC. Pressure looks to be around 924.

Uhhhh, what?

[Siker]

[txwatcher91]

I may be wrong but I believe last year in the Atlantic that it was shown with several cat 5s that the surface winds at the peak was similar to flight level winds and even stronger in some instances, confirmed by dropsonde data that showed a similar profile.

[typhoonty]

This is not a category 4 hurricane by any stretch of the imagination right now. Keeping it at cat 4 is a disservice to the public.

The SFMR does have a known significant high bias, and flight-level winds don't support cat 5 yet. But it is up to CPHC. Pressure looks to be around 924.

Respectively disagree, Craig. SFMR doesn't have a significant high bias and if it did there would be a ratio like FL winds. Now you could argue SFMR should be discounted when the values are higher than FL, which has happened a few times with Lane. However, even based on the amount I could conceivably drop the speeds due to this discrepancy, I still wouldn't go lower than 140-145 knots.

[Chris90]

I'd just like to quickly mention they called the SFMR readings for Irma into question in her TCR, but I never saw them call any of the SFMR readings for Maria into question. So that high bias seemed to be situational last year. I thought they made some alterations to the SFMR algorithm back in 2015 to correct some biases, so it was more accurate. I think some eyewall dropsondes will help give a better idea of how accurate that 154kt reading for Lane is.

[BYG Jacob]

I may be wrong but I believe last year in the Atlantic that it was shown with several cat 5s that the surface winds at the peak was similar to flight level winds and even stronger in some instances, confirmed by dropsonde data that showed a similar profile.

Both Irma and Maria last year

[CrazyC83]

This is not a category 4 hurricane by any stretch of the imagination right now. Keeping it at cat 4 is a disservice to the public.

The SFMR does have a known significant high bias, and flight-level winds don't support cat 5 yet. But it is up to CPHC. Pressure looks to be around 924.

Respectively disagree, Craig. SFMR doesn't have a significant high bias and if it did there would be a ratio like FL winds. Now you could argue SFMR should be discounted when the values are higher than FL, which has happened a few times with Lane. However, even based on the amount I could conceivably drop the speeds due to this discrepancy, I still wouldn't go lower than 140-145 knots.

I was thinking based on findings from Irma, Jose and Maria. I would still go 140-145 kt, but if the SFMR was taken at face value that would support 155 kt. We'll know in about 90 minutes what they decide.

[Kazmit]

The satellite view of this looks a lot like Jose from last year- similar stadium eye, banding, and intensity.

[CrazyC83]

Dropsonde: pressure 926 mb (927/13).

[NotoSans]

Looks like LANE is near its peak now as central pressure has started to level off. Satellite imagery also shows that central convection in the western side has started to warm.

[CrazyC83]

I believe 926 is the lowest actually measured pressure ever in the central Pacific. Ioke was lower (as low as 915) but that was only from satellite estimates.

[NotoSans]

I believe 926 is the lowest actually measured pressure ever in the central Pacific. Ioke was lower (as low as 915) but that was only from satellite estimates.

Lowest pressure recorded by recon for a CPAC hurricane would be 929mb for John'94 IIRC.
(Ironically CPHC assessed John's peak intensity at 150 knots and I guess that's what we should except for a typical 929-mb CPAC hurricane.)

[Iune]

I believe 926 is the lowest actually measured pressure ever in the central Pacific. Ioke was lower (as low as 915) but that was only from satellite estimates.

Lowest pressure recorded by recon for a CPAC hurricane would be 929mb for John'94 IIRC.
(Ironically CPHC assessed John's peak intensity at 150 knots and I guess that's what we should except for a typical 929-mb CPAC hurricane.)

If I remember right, the 929 mbar pressure was when John was weaker. The 150 kts didn't have a recon measured pressure.

[BYG Jacob]

VDM says that SFMR was legit, lets see what the CHPC says.

[BYG Jacob]

CHPC went with 140 knots and 922 mb. Fair enough, I guess.

[NotoSans]

Special advisory within the next hour.

...NOAA AIRCRAFT FINDS THAT LANE HAS STRENGTHENED TO A CATEGORY 5
HURRICANE...

Data from the NOAA P-3 aircraft indicate that Lane has continued to
intensify this afternoon. Maximum sustained winds have increased to
near 160 mph (260 km/h), making Lane an extremely dangerous category
5 hurricane. A special advisory will be issued within the hour.


SUMMARY OF 620 PM HST...0420 UTC...INFORMATION
----------------------------------------------
LOCATION...14.5N 154.0W
ABOUT 375 MI...605 KM SSE OF KAILUA-KONA HAWAII
ABOUT 535 MI...860 KM SSE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...160 MPH...260 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...922 MB...27.23 INCHES