Hurricane Dean

[Marcus Opitz]

I completely agree. Look at how bad New Orleans suffered after Katrina, and that was only a CAT 3. If the United States isn't prepared for that, you have to believe that Mexico isn't.

Not exactly sure of the motives, but some of these chasers aren't doing it for money. Apparently, "Hurricane Josh" (from the Eastern Wx forum) owns an advertising agency, and money isn't really an issue for him. I can't imagine that he's doing this to make a quick buck if that is indeed the case.

Some people just like the adrenaline... and what would make your adrenaline higher than a CAT 5 'cane in Mexico?

I think some good knowledge of jungle survival would be highly recommended as well!

 

[John Peters]

The most recent HWRF run puts dean into the Yucatan at 873 mb

I think it's quite possible that Dean won't become a cat 5 before landfall. It seems like the storm has had a lot of trouble maintaining a stable eyewall and symmetric CDO since the eastern caribbean.

Both HWRF and GFDL indicate that the storm could re-intensify to cat 3 before the second landfall.

 

[MClarkson]

The further south Dean tracks, the less prepared and more vulnerable the populations. Cancun could have taken this storm without too much loss of life... I am not sure what will happen in Belize and the southern Mexican Yucatan.

 

[Bill Hark]

I really hope that "Hurricane Josh" doesn't vanish after the area is hit by a CAT 5, either from storm surge or the increase in lawlessness during the aftermath. If he comes through, I can't wait to see his video and stills.

I won't criticize his decision to go though I think the risk is very great. I wouldn't do such a chase on my own.

Bill Hark

 

[Howard Robinson]

Looks like the outer rainbands are on Cancun radar now, and current track puts it over Cancun in a few hours.

 

[Perry Williams]

Based on a new vortex fix (1923z) which finally came across the wire, Dean is on the verge of being a cat-5. Central pressure listed as 918 mb, and max flight level winds in the NE eyewall of 151 kts.

URNT12 KNHC 201945
VORTEX DATA MESSAGE AL042007
A. 20/192320Z
B. 18 DEG 05 MIN N
083 DEG 39 MIN W
C. 700 MB 2399 M
D. 120 KTS
E. 060 DEG 15 NM
F. 151 DEG 151 KTS
G. 060 DEG 15 NM
H. 918 MB
I. 9 C/ 3037 M
J. 19 C/ 3043 M
K. 18 C/ NA
L. CLOSED WALL
M. C18
N. 12345/7
O. 0.03/1 NM
P. AF303 1404A DEAN 0B 15
MAX FL WIND 151 KT NE QUAD 1918Z

 

[MClarkson]

The pressure is down to 918mb and FL wind max was 151kt... high end Cat 4. The generally westward track continues, the eye and CDO could stand to be a little more symetrical...

 

[cdcollura]

Good day all...

I love chasing hurricanes, and been through many bad ones as well.

I have Andrew 92, Katrina 05, Charley 04, and many others under my belt ... But although I am down-right CRAZY, I never want to even be labeled as STUPID.

Here are my NEGATIVES on why I am not just jetting to the Yucatan, renting a car / SUV, and chasing Dean.

1). Night landfall (like 4 AM or so).

2). Storm core keeps shifting more W (not the expected WNW) on each advisory / forecast package.

3). Landfall may be on (or even south) of Mexican / Belize border.

4). If that verifies ... Jungles, little or no road networks.

5). You cannot bring 2 weeks of food, water, and survival gear on an airplane.

6). Anarchy and corrupt government, looting, disorder afterwards.

7). I do not have a gun, and will not buy one to protect myself there AFTER the storm.

8). Started a new job, and being stuck in the jungle for 2 weeks with no comm whatsoever will not explain why I should not be fired as I come back sometime in September.

9). Basically, Chris Collura would essentially disappear from the USA for 2 weeks or so.

10). I have not watched enough "Survivorman" on DISC yet.

11). "Dean" is my middle name ;-(

12). Parking garages above 30 feet MSL are hard to find on the east side of the bay of Chetumal. Surge is another issue, as the photo ops we had in Katrina in 05 won't happen since it will be dark.

13). Winds sustained at 150-160 MPH (this is at-least) and a 30% rule on gusts (near 200 MPH) - This is basically an EF-5 tornado (over 200 MPH peak winds) about 30-40 miles wide and at night - THINK about it!

Just my thoughts. But remove some of these "negatives" and I might re-consider (won't happen in 12 hours) ;-(

 

[John Peters]

Based on a new vortex fix (1923z) which finally came across the wire, Dean is on the verge of being a cat-5. Central pressure listed as 918 mb, and max flight level winds in the NE eyewall of 151 kts.

URNT12 KNHC 201945
VORTEX DATA MESSAGE AL042007
A. 20/192320Z
B. 18 DEG 05 MIN N
083 DEG 39 MIN W
C. 700 MB 2399 M
D. 120 KTS
E. 060 DEG 15 NM
F. 151 DEG 151 KTS
G. 060 DEG 15 NM
H. 918 MB
I. 9 C/ 3037 M
J. 19 C/ 3043 M
K. 18 C/ NA
L. CLOSED WALL
M. C18
N. 12345/7
O. 0.03/1 NM
P. AF303 1404A DEAN 0B 15
MAX FL WIND 151 KT NE QUAD 1918Z

Thanks for the info Perry. What does 151 kts translate to at the surface?

 

[Jeff Snyder]

Thanks for the info Perry. What does 151 kts translate to at the surface?

151kts leads to an ESTIMATE of ~135kts at the surface. It is very important to remember, however, that this is a rough estimate. The wind profile near hurricane eyewalls can be very complex, and they can vary from storm to storm (and from time to time in the same storm). Some studies have shown that the proper reduction factor is actually closer to 0.65-0.75. From what I've seen, it's certainly more likely that the 0.9 reduction factor leads to an overestimate much more often than an underestimate. Fortunately, we have dropsonde and SFMR data that can help corroborate an intensity estimate derived from a Fl-level wind reduction.

 

[cdcollura]

Good day all,

Thanks for the info Perry. What does 151 kts translate to at the surface?

151 Knots is almost 174 MPH ... The surface correction is usually 90%, so 174 * 0.9 is about 157 MPH.

Call it 160 MPH on the next advisory (usually the advisories round up or down each 5 MPH), and voila, you have a minimal cat-5 (over 155 MPH) ;-)

The 90% is for a well-mixed eyewall boundary layer over a marine (ocean) environment. Over land, or when cool air is involved, this can drop to 50% (also common over cooler N atlantic waters).

Over the W Caribbean, water near 90 F, no shear, it should be 90%.

 

[Bob Schafer]

Is anyone able to decode what the "894" at the end of this dropsonde data implies? There's been some noise about this on easternuswx.com. Thanks.

http://www.nhc.noaa.gov/text/MIAREPNT3.shtml?

 

[Gabe Garfield]

Just as an FYI, the last Atlantic Basin hurricane to make landfall as a Category Five hurricane was Andrew in 1992. Even though we've had several Category Five storms since Andrew, most were weakening upon landfall. It is very likely that this will not be the case with Dean, as it appears that he will be on the upswing at landfall.

Gabe

 

[John Peters]

I still think it's possible that dean will not become a category five before landfall. The most recent forecast advisory suggests the formation of concentric eyewalls once again. This may inhibit further strengthening of the inner eyewall. Reconnaissance data has also suggested that 130kts is somewhat generous of an estimate. Recent IR imagery has shown some asymmetry of the coldest CDO cloud tops (similar to behavior the storm has been exhibiting throughout the caribbean).

 

[cdcollura]

Very little is understood about eyewall replacement cycles.

The constant re-structuring of a hurricane core makes a 5-10 MPH change nearly impossible to predict with current tools and technology.

This is where the term "fluctuations" in strength of a hurricane that has peaked at max intensity come into play.