Hurricane Félix: RECON Discussion

[brunota2003]

Hmmm...Is it because the winds are so strong that the dropsondes are not reporting wind at the surface? Or the waves? That is, I think the second eyewall drop that showed no surface values.

No, it's because the mandatory 925mb level is too close . . . it doesn't have time to take two readings within a split second (i.e. much less than 50 meters).

Ah, ok. Thanks! I learnt me something new over Labor Day weekend

[benny]

the latest data had an unflagged 142KT

I've never heard of surface winds being higher than flight level winds. FL winds are only 147kts and SFRM is reporting 142kts...158kts..and 163kts...so either something is wrong or this beast is on steroids.

158 and 163 were wrong . . . ignore them like they don't exist . . .

However, the 142 was not flagged . . . which means it should be accurate. And yes, it is possible to have reduction factors >1, sometimes even nearing 1.4, though it is rare . . .

The 3 is there because of the exceptionally fast transition from high to low winds. It isn't "wrong" it is just flagged as suspect because of time constaints.

Looks kinda like Rita to me.

[Derek Ortt]

this looks to be about 150KT

[KBBOCA]

Mmm...pressure at 5 pm was 956...since 5 pm, if the pressure right now is 934, that would be 22 millibar drop. Coming out to, using a 3 hour (5 pm to 8 pm) division, 7.33333 millibar drop per hour!!! That is absolutely insane!

Can anyone tell me how this compares with Wilma's intensification rate at her peak? edit: (Or is it Rita I mean? Sorry, it's late here in my time zone (I'm in GMT, so near midnight.) Fuzzy brain.)

[LAwxrgal]

When are they going to come out with a special warning that this is a Cat 5?

[RL3AO]

this looks to be about 150KT

Do you think we can get to 180 mph sustained?

[Brent]

this looks to be about 150KT

*very anxiously awaits the 8pm advisory*

[CrazyC83]

Mmm...pressure at 5 pm was 956...since 5 pm, if the pressure right now is 934, that would be 22 millibar drop. Coming out to, using a 3 hour (5 pm to 8 pm) division, 7.33333 millibar drop per hour!!! That is absolutely insane!

934 seems the best estimate - an eye drop with 24 kt surface winds had 936. Typically it is a 1 mb decrease for every 10 kt of winds at the surface (rounded down).

I think the winds are actually 130-135 kt at this point. I'm not convinced yet that it is a Cat 5. What will the NHC say though?

[WindRunner]

this looks to be about 150KT

Does this come out of reading the drops? Or do you have some other particular reason for this?

[Derek Ortt]

I'm more worried about how large this is going to become than the winds

[Ptarmigan]

I'm more worried about how large this is going to become than the winds

Large hurricanes are a lot more dangerous. The Gulf Coast saw that in 2005 with Katrina.

[WindRunner]

URNT12 KNHC 022338
VORTEX DATA MESSAGE AL042007
A. 02/2307Z
B. 13 DEG 40 MIN N
72 DEG 43 MIN W
C. 700 MB 2601 M
D. 163 KT
E. 45 DEG 12 NM
F. 142 DEG 152 KTS
G. 056 DEG 12 NM
H. 936 MB
I. 25 C/ 2745 M
J. 26 C/ 2806 M
K. 4 C/ NA
L. CLOSED WALL
M. C15
N. 12345/7
O. 1/1 NM
P. N0AA2 0906A FELIX OB 10
MAX FL WIND 152 KT NE QUAD 2252Z
MAX SFC WND 163 FROM SFMR NE QUAD
EXTREME TURB NE EYEWALL

Looks like they believed the 163kt SFMR reading . . . via part D and notes!

[CrazyC83]

163 kt surface winds found in the Vortex message.

[Scorpion]

Whoa.... not sure when the 152 kt came in. That plus the 163 kt convinces me this is a Cat 5

[CrazyC83]

Whoa.... not sure when the 152 kt came in. That plus the 163 kt convinces me this is a Cat 5

I'm not sure if I believe it though; the 152 would round down to 137 kt surface.

[benny]

163 kt surface winds found in the Vortex message. That equals 147 kt at the surface with a 90% reduction.

Umm.. that's 163 at the surface. Not a flight-level reduction. The max flight levels winds were 152, equating to 135-140 at the surface. Obviously not the standard reduction is the most useful here. This is really historic actually. I don't think the SFMR has ever measured 163 kt

[Brent]

163 kt?!

936 however... very high if it's THAT strong.

[Scorpion]

I wonder what intensity the NHC will use then

[CrazyC83]

163 kt surface winds found in the Vortex message. That equals 147 kt at the surface with a 90% reduction.

Umm.. that's 163 at the surface. Not a flight-level reduction. The max flight levels winds were 152, equating to 135-140 at the surface. Obviously not the standard reduction is the most useful here. This is really historic actually. I don't think the SFMR has ever measured 163 kt

I realized it and corrected it. I am not convinced that is accurate though as it seems out of line with the pressure and the flight-level readings. I'm still estimating 135 kt in reality, maybe 140 kt.

[wxmann_91]

163 kt surface wind... how is that possible with such a high pressure? Must be something called strong pressure gradient + strong convection bringing gusts down to the sfc.