NOW: Hurricane Rita

[Dave Lewison]

Anyone else notice that Buoy #42001 was hit pretty much dead on and only recorded a peak gust of around 105kts and sustained of less than 80kts? According to the lat/lon of the buoy and the extrapolated path of Rita, this buoy was inside the western edge of the eye. Minimum pressure recorded was about 925mb, so it got pretty darn close to dead center. For a CAT4, shouldn't these wind values have been much higher?

 

[Jeff Snyder]

Originally posted by Dave Lewison
Anyone else notice that Buoy #42001 was hit pretty much dead on and only recorded a peak gust of around 105kts and sustained of less than 80kts? According to the lat/lon of the buoy and the extrapolated path of Rita, this buoy was inside the western edge of the eye. Minimum pressure recorded was about 925mb, so it got pretty darn close to dead center. For a CAT4, shouldn't these wind values have been much higher?

I'd think that the wave action (especially being >30') could significantly impact "true" wind speed measurements. I'd imagine that the main cause for this would likely be from the fact that the platform/buoy would "tilt" on the front and back part of the wave as the plane of water tilts up and down. I'd imagine this would lead to considerable wind measurement errors.

 

[Morgan Palmer]

Also, I think both propeller and cup anemometers have a tendency to underreport extreme wind speeds because of the aerodynamic forces... that is, the mere fact that the propellers or cups are there might cause some opposite force to the wind, or that the spinning objects might be subject to aerodynamic drag.

I remember hearing one time this was especially true with the "cup" anemometers, though I'm not sure about the propellers or impellers, or whatever they're called.

Maybe others can shed light on this.

 

[B Ozanne]

Maybe others can shed light on this.

I've always said that cups miss the gusts but over long periods they raise the average wind speed. They have inertia and will keep spinning after the wind slows, this also makes them slow to spin up during gusts.

On Mount Washington we have a 3-cup for the summer. It comes down when the winds go over 35mph, and it doesn't go anywhere near icing conditions. The rest of the time we rely on a modified aircraft static pitot tube. It's response time to changes in wind speed is amazing.

Oh, about 42001. Its in the middle of the ocean! Going up and down 40 foot waves. That is one of the biggest buoys I have ever seen but I imagine it spent quite a bit of time on its back.

Also, is tthe gust reported by those buoys from the previous 15 minutes or is it the whole hour? Standard observations list the peak gust in the 15 minutes before the ob. Peak gust for the hour would be reported in the remarks. I guess the same question applies to the sustained wind as well. Standard obs include the 2 minute average speed prior to the ob, not the whole hour.

 

[Jeff Lawson]

Originally posted by Chris Lott
I heard one report today that if the high over Texas was to move out that Rita could again turn west. Does anyone see this happening?

The high "moving out" would force the storm to turn poleward. In fact, that's exactly what's expected: as the high retreats eastward, Rita should gradually turn poleward as it tracks around the western periphery of the ridge. For the storm to turn back to the west prior to landfall, the high would have to build and stay put.

 

[david hilbert]

NOAA bouys?

I posted this earlier on the "Rita surge" topic, but it's all too applicable now-

I agree. I'm from the Mississippi Coast but was in L.A. when Katrina hit. I haven't got a clear understanding on why 8-12 hours before landfall in Louisiana there was no difinitive storm surge gauge, eventhough NOAA has dotted the Gulf with bouys that measure such, i.e "Warning, NOAA measures a consistant 30 foot storm suge that will wash 1/2 mile inland in coastal Mississippi..." This is exactly what the storm surge did, and I've been to ground zero in Waveland and Bay St Louis to see it! Any info on why NOAA or NHC can't give a percisie measurement of a surge in the gulf as a storm is hours away from landfall is appreciated. Hell, they are supposed to be able to read an approaching tsunami, correct?

So, if you have the answer, let me know.

Why is stormtrack.org so revelvant?

I streamed WLOX TV/Biloxi sat Aug 28 and caught the 11pm chief meteorolisht update (aka Mike Redor http://wlox.com/Global/story.asp?S=64099&nav=menu40_3). This quailfied blok said Katrina would be a kat-2 and no Camile. He even started his live cast to Harrison/Hancock county with, "This is no Camile, and let me show you why...."

I lived on the MS coast for the last 20 yeras, most in the casino industry, 15K employees. So, I wonder, how many people watched his report Sunday at 11pm and breathed a sigh of releigh, only to be met with a 30ft surge? WLOX is the ONLY network affliate other then cable. PS - when the final toll is in, "think Thiland." Been there, seen it...

So - I vented!

 

[Benjamin Sipprell]

But we have two highs, right ... one situation over the mid-Atlantic and another over TX? And the weak point situated over the TN valley ...

http://www.ssd.noaa.gov/PS/TROP/DATA/RT/nw...tl-wv-loop.html

Alright, isn't it possible for any of the two upper level high pressure centers to steer the storm ... one into TX/LA border and another into Brownsville?

This is like a tug of war ... with most models give credence to the eastern high pressure as the evident forcing/movement of the storm.

Thoughts?

 

[HAltschule]

With all due respect, I'm not sure I understand what relevant information your trying to add to this conversation? Did I miss something? :?

 

[B Ozanne]

I haven't got a clear understanding on why 8-12 hours before landfall in Louisiana there was no difinitive storm surge gauge, eventhough NOAA has dotted the Gulf with bouys that measure such

I look at those NOAA Buoys all the time and they don't measure the storm surge. As far as I know you can't do that in the middle of the ocean. So called "tide guages" are fixed to the ground, never floating in the ocean.

Just wanted to clear that up. The buoys do provide valuable information in the form of sea surface and air temp, wave height/period, pressure and wind.

Check out www.ndbc.noaa.gov

 

[Benjamin Sipprell]

Latest RECON reports the inner eyewall to be ragged ... aids the conclusions everyone was drawing about the ERC ... yet reports are coming in that the eye itself is closed ... can this be the start of things to come?

 

[Joshua Crisp]

What? What things to come what would it meen?

 

[HAltschule]

I'll tell you what....IR Satellite imagery sure looks like Rita took a nice West to West-Southwest jog for a few hours. I still have serious concerns for Galveston and Houston, TX as a direct hit landfall!!

Man this internet is so S L O W tonight. Must be a ton of surfers.....

Edit: Corrected b/c my spelling sucks tonight.

 

[Benjamin Sipprell]

Originally posted by Joshua Crisp
What? What things to come what would it meen?

I was just remarking if this ragged inner eyewall collapse is now being noted will we see the contracting of the outer eyewall leading to the intensification of Rita? Just keep watching those RECON's ... NHC will have a new advisory out in 30 min (note its 8:30 MT as I write this)

 

[BrandonWhittington]

Is it me, or is the eye of Rita wobbling more to the west than northwest in the latest satellite images?

 

[Joshua Crisp]

yes she is, I have been watching it and it just started a slight wobble to the west...