EPAC Tropical Action 2012

[Chicago Storm]

24hr MIMIC loop:

[wxmx]

Wooohooo! first major...annular and landfall at close to cat 2 in the latest advisory

[phil882]

Wooohooo! first major...annular and landfall at close to cat 2 in the latest advisory

I'd certainly disagree with the annular classification from the NHC. Just because a hurricane lacks outer rain bands does not automatically make it an annular hurricane. Knaff et al. (2008).pdf gives great insight on the unique qualities that define Annular Hurricanes and Table 3 clearly lists a set of variables that if compromised indicate a storm is unlikely to be annular.

Rc stands for radius of coldest azmuthally averaged brightness temperature, which in Bud's case is certainly less than 50 km. Detla T eye stands for eye temperature, which is certainly warmer than 15 degrees C at this time. SHRD stands for vertical wind shear from 200-850 hPa which is on the increase and is about to exceed 11.3 m/s. All of these three variables suggest that Bud HAS NOT evolved into an Annular storm. It cheapens the peer reviewed literature to suggest otherwise.

[wxmx]

I'd certainly disagree with the annular classification from the NHC. Just because a hurricane lacks outer rain bands does not automatically make it an annular hurricane. Knaff et al. (2008).pdf gives great insight on the unique qualities that define Annular Hurricanes and Table 3 clearly lists a set of variables that if compromised indicate a storm is unlikely to be annular.

Rc stands for radius of coldest azmuthally averaged brightness temperature, which in Bud's case is certainly less than 50 km. Detla T eye stands for eye temperature, which is certainly warmer than 15 degrees C at this time. SHRD stands for vertical wind shear from 200-850 hPa which is on the increase and is about to exceed 11.3 m/s. All of these three variables suggest that Bud HAS NOT evolved into an Annular storm. It cheapens the peer reviewed literature to suggest otherwise.

Yep, SHIPS AHI says no go... Stewart got a bit overexcited

Eye has been clouded on IR...probably downhill from here on

[phil882]

Yep, SHIPS AHI says no go... Stewart got a bit overexcited

Eye has been clouded on IR...probably downhill from here on

Agreed, this storm has peaked and we will probably be Cat 2 or 1 at landfall tomorrow, not unlike the NHC's forecast. Interesting case study though, because the models were fooled in the 48-72 hour range when Bud took longer than normal to intensify. I think its an interesting example how TC intensity can have a significant impact on track given that there was no dominant subtropical high steering the storm westward. If Bud had struck around as a mid range TS, the stalling track before landfall might have been more realistic.

[Sickman]

I'd certainly disagree with the annular classification from the NHC. Just because a hurricane lacks outer rain bands does not automatically make it an annular hurricane. Knaff et al. (2008).pdf gives great insight on the unique qualities that define Annular Hurricanes and Table 3 clearly lists a set of variables that if compromised indicate a storm is unlikely to be annular.

Rc stands for radius of coldest azmuthally averaged brightness temperature, which in Bud's case is certainly less than 50 km. Detla T eye stands for eye temperature, which is certainly warmer than 15 degrees C at this time. SHRD stands for vertical wind shear from 200-850 hPa which is on the increase and is about to exceed 11.3 m/s. All of these three variables suggest that Bud HAS NOT evolved into an Annular storm. It cheapens the peer reviewed literature to suggest otherwise.

I never once thought "annular" with this one. Thanks for clarifying that.

[am19psu]

Stewart got a bit overexcited

[dan88]

Unsurprisingly, recon found a far weaker storm than yesterday, peak 52kt flight level winds in the SE quad and 63kts in the NW quad at 700mb, 982.7 extrap pressure.

Storm is a decent ways north of the advisory position, with the center roughly 18.9N compared to the 18.4N the advisory position had it 2 hours ago. It is located at almost exactly at the half way point between the 15z advisory and the forecast 00z location.

[HurricaneJosh]

lolz

[dan88]

Advisory puts it at 70kt/990mb.

[HurricaneJosh]

Advisory puts it at 70kt/990mb.

Seems charitable.

[Ed Lizard]

May not even make it to MX as a cane...

URPN12 KNHC 251739

VORTEX DATA MESSAGE EP022012

A. 25/17:09:10Z

B. 18 deg 52 min N

105 deg 28 min W

C. 700 mb 3037 m

D. NA

E. NA

F. 201 deg 52 kt

G. 142 deg 30 nm

H. EXTRAP 990 mb

I. 10 C / 3050 m

J. 22 C / 3047 m

K. 3 C / NA

L. NA

M. NA

N. 1345 / 7

O. 0.02 / 1 nm

P. AF302 0202E BUD OB 14

MAX OUTBOUND AND MAX FL WIND 63 KT NW QUAD 17:22:10Z

SLP EXTRAP FROM 700 MB

;

[HurricaneJosh]

I'm surprised the 2 pm PDT advisory keeps it as a hurricane. The IR presentation is pathetic. I'd be surprised if that thing really has winds of 65 kt.

[isohume]

It looks like crap.

[Quincy]

Bud looks like a Dud. Could very well be a Tropical Depression by morning.

[Sickman]

Bud's pulling a Don.

[HurricaneJosh]

Bud's pulling a Don.

Totally.

[HurricaneJosh]

I mean, WTF is that??

[HurricaneJosh]

Climo really kicked azz with this one. There's only been one May hurricane landfall on MX's Pacific coast since 1949, and there's a reason for that.

It's hard to believe this was a beautiful, 100-kt cyclone heading for shore 24 hr ago. Wow.

[lester]

[HurricaneJosh]

:lmao:

[HurricaneJosh]

lester, did you make that?

[phil882]

Its quite impressive how the storm is reaching peak intensity right under the supressed phase of the Kelvin wave. I think the main focus here is that the shear has decreased over the storm (thanks to the easterly flow being replaced by light and variable upper level flow). This perhaps is more important than than the large scale convergence aloft, which can be easily overcome from a dynamic process such as strong latent heat release. However, this storm is about to encounter the westerly flow on the back side of the suppressed Kelvin wave phase. Since this will also be combined with an upper level environment that is favorable for sinking motion (note the distinct lack of convection outside of the inner core of Bud), the storm will be very susceptible to dry air intrusions, and we will probably see Bud fall apart as fast as it intensified over the past 24 hours.

Climo really kicked azz with this one. There's only been one May hurricane landfall on MX's Pacific coast since 1949, and there's a reason for that.

It's hard to believe this was a beautiful, 100-kt cyclone heading for shore 24 hr ago. Wow.

Not just climo Josh... sea surface temperatures were actually in the 28 degree Celsius range overhead of the system. Bud fell apart as fast as it did because of the factors I highlight above. If a convectively coupled kelvin wave (CCKW) had been moving overhead rather than a suppressed KW phase, I think the outcome might have been significantly different.

[lester]

lester, did you make that?

yep

[HurricaneJosh]

Not just climo Josh... sea surface temperatures were actually in the 28 degree Celsius range overhead of the system. Bud fell apart as fast as it did because of the factors I highlight above. If a convectively coupled kelvin wave (CCKW) had been moving overhead rather than a suppressed KW phase, I think the outcome might have been significantly different.

I wasn't talking about SSTs-- I was talking about the environmental conditions. Todd Kimberlain, an EPAC expert, alluded to the climatology in a Facebook post today, remarking, "Landfalling May hurricanes in Mexico are quite uncommon. There's a reason for that since the atmosphere is rarely favorable enough to support such an occurrence."

[phil882]

I wasn't talking about SSTs-- I was talking about the environmental conditions. Todd Kimberlain, on a Facebook post today, alluded to the climatology, remarking, "Landfalling May hurricanes in Mexico are quite uncommon. There's a reason for that since the atmosphere is rarely favorable enough to support such an occurrence."

Fair enough... although my counter argument is that its exceptionally rare in the first place to have a major hurricane in the month of May. I think Bud is to date the second most intense hurricane to ever occur in the East Pacific basin in the month of May. Its easy for hurricanes to be climotologially unfavorable for landfall when they are climotologically unfavorable to occur in the first place.

[HurricaneJosh]

yep

[Brent]

This is worse than Don... at least this was at one time very recently impressive

[HurricaneJosh]

This is worse than Don... at least this was at one time very recently impressive

Agreed.

And, by the way, it's degenerated into a remnant low this morning. lolz

[phil882]

Agreed.

And, by the way, it's degenerated into a remnant low this morning. lolz

If even that... I don't think a center even exists anymore looking at visible imagery. That was a pretty spectacular collapse.