SW Indian Ocean: TD Alvin Ex-Bertie

[senorpepr]

Those are only general guidance though. Also that list will be in one minute averages so it won't correlate with the BOM's advisories.

Yes... the official BoM advisory, which is set at 85kt, is a ten-minute average. To convert it to the "American-standard" of a one-minute average, it would be around 97kt. So, in reality, the Dvorak scale is pretty accurate to Bertie-Alvin.

[Forecaster Colby]

Oh....okay. Didn't know they used 10 minute there.

[wxmann_91]

WHAT BEAUTY!!!

[Forecaster Colby]

That is one of the prettiest storms I've ever seen. Wow.

[senorpepr]

Oh....okay. Didn't know they used 10 minute there.

10-minute is officially the WMO standard, but the US beats to a different drum. (Although, personally, I perfer the 1-minute standard better)

[P.K.]

I'm going to disagree with you here (As we use ten minute averages here )....

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR SOUTH-WEST INDIAN OCEAN

GLOBAL MODEL DATA TIME 12UTC 22.11.2005

TROPICAL CYCLONE BERTIE ANALYSED POSITION : 12.3S 90.4E

VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

12UTC 22.11.2005 12.3S 90.4E MODERATE

00UTC 23.11.2005 13.2S 89.3E MODERATE LITTLE CHANGE

12UTC 23.11.2005 14.3S 88.9E MODERATE LITTLE CHANGE

00UTC 24.11.2005 14.8S 88.0E MODERATE WEAKENING SLIGHTLY

12UTC 24.11.2005 15.4S 86.5E MODERATE WEAKENING SLIGHTLY

00UTC 25.11.2005 15.4S 84.6E WEAK WEAKENING RAPIDLY

12UTC 25.11.2005 14.3S 82.3E WEAK WEAKENING SLIGHTLY

00UTC 26.11.2005 14.0S 79.8E WEAK WEAKENING SLIGHTLY

12UTC 26.11.2005 13.5S 78.1E WEAK WEAKENING SLIGHTLY

00UTC 27.11.2005 13.3S 75.9E WEAK LITTLE CHANGE

12UTC 27.11.2005 BELOW TROPICAL STORM STRENGTH


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE

RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS

AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT

MET OFFICE, EXETER, UK

[senorpepr]

I'm going to disagree with you here (As we use ten minute averages here )....

Fair enough. My only reasoning to perfering the one-minute average is because it is representative of what is going on at that current time whereas the 10-minute averages tends to "smooth" out the peaks and lulls. That and fahrenheit (which is a more high-res scale than celsius) are about the only two scales used in American that I perfer. Otherwise, I'm for the metric system. But that's off-topic

[Forecaster Colby]

Yeah, Metric makes sense when you have multiple units of the same measure (feet, inches), whereas the more precise american units make sense for a single unit (temperature). The one exception for me is millibars, which are much easier to use than inches of Hg.

[P.K.]

That is what gusts measurements are for. To be fair it doesn't matter what parameter you measure it will fluctuate due to turbulence etc.( Even if we do assume Taylor's frozen turbulence hypothesis)

You just need a more sensitive thermometer. I suggest you get a PRT one, that should be nice and accurate. I'm fully metric though as you might be able to tell.

[senorpepr]

Yeah, Metric makes sense when you have multiple units of the same measure (feet, inches), whereas the more precise american units make sense for a single unit (temperature). The one exception for me is millibars, which are much easier to use than inches of Hg.

I've always been more used to millibars for pressure, since a bar is a unit of pressure like a liter is a unit of liquid. I even had a bicycle pump that measured in bars when I was younger. Today, I'm so used to computer models having data in millibars that it is actually a pain having to convert to inches of Hg when writing a TAF (terminal aerodrome forecast). Thankfully I have that conversion memorized: mb*0.029529884="Hg

[senorpepr]

That is what gusts measurements are for. To be fair it doesn't matter what parameter you measure it will fluctuate due to turbulence etc.( Even if we do assume Taylor's frozen hypothese hypothesis)

You just need a more sensitive thermometer. I suggest you get a PRT one, that should be nice and accurate. I'm fully metric though as you might be able to tell.

lol

As for the sensitive thermometers, I was speaking more on the terms of public use. It's easier to say 74°F than 23.3°C. Then again, when it comes to forecasting, I think strickly in terms of celsius. Matter of fact, over the years of having to forecast in celsius and then convert to fahrenheit for the "common folk", I've memorized much of the scale's conversions. I know 10°C is 50°F, etc., without having to do the math.

[HURAKAN]

TRACY'S COUSIN!!!

[Forecaster Colby]

Not really...Tracy was nuts.

[HURAKAN]

Not really...Tracy was nuts.

That's why is the cousin, not the twin!!!!

[HurricaneBill]

I was on some website and they gave hourly sustained winds.

Is there a way to convert 1-hour average sustained winds to 1-minute?

[P.K.]

It's easier to say 74°F than 23.3°C. Then again, when it comes to forecasting, I think strickly in terms of celsius.

Yes but then it is easier to be wrong when making a forecast.

There is no public warning on their website yet.

WTIO30 FMEE 221845
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER : 1/5/20052006
1.A INTENSE TROPICAL CYCLONE 5
2.A POSITION 2005/11/22 AT 1800 UTC :
WITHIN 20 NM RADIUS OF POINT 12.1S / 90.3E
(TWELVE DECIMAL ONE DEGREES SOUTH AND NINETY DECIMAL THREE DEGREES
EAST)
3.A DVORAK ANALYSIS : 6.0/6.0 PLUS /D 1.5/24 H
4.A CENTRAL PRESSURE : 930 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 100 KT
6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 220 SE: 300 SO: 220 NO: 150
50 KT NE: 080 SE: 080 SO: 080 NO: 080
7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 800 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP
1.B FORECASTS:
12H: 2005/11/23 06 UTC: 12.5S/89.8E, MAX WIND=100KT.
24H: 2005/11/23 18 UTC: 13.2S/89.0E, MAX WIND=100KT.
36H: 2005/11/24 06 UTC: 13.9S/87.8E, MAX WIND=100KT.
48H: 2005/11/24 18 UTC: 14.4S/86.3E, MAX WIND=090KT.
60H: 2005/11/25 06 UTC: 14.4S/84.3E, MAX WIND=090KT.
72H: 2005/11/25 18 UTC: 14.3S/82.1E, MAX WIND=080KT.
2.B OTHER INFORMATIONS:
T=CI=6.0
INTENSE TROPICAL CYCLONE 05-BERTIE INTENSIFIED DURING THE PAST FEW
HOURS.
THE SYSTEM IS RATHER SMALL BUT SYMETRIC AND WELL ORGANIZED ABOUT A
CLEAR
EYE.
BERTIE IS EXPECTED TO KEEP ON TRACKING SOUTH-SOUTHWESTWARDS FOR A
WHILE,
BEFORE TRACKING WESTWARDS ON THE NORTHERN EDGE OF THE BUILDING
SUBTROPICAL HIGH PRESSURES SOUTH OF THE SYSTEM.
THE SYSTEM IS EXPECTED TO WEAKEN AFTER THURSDAY NOV 24 DUE TO THE
INCREASING VERTICAL WIND SHEAR.=
NNNN

[Forecaster Colby]

930mb, 100kt? WOW, that was fast!

[HurricaneBill]

10 min sustained = 100 kts

100 X 1.125 = 112.5 kts = 1 min sustained

112.5 X 1.15 = 129.375 mph

Bertie-Alvin is just shy of Category 4 status!

[senorpepr]

10 min sustained = 100 kts

100 X 1.125 = 112.5 kts = 1 min sustained

112.5 X 1.15 = 129.375 mph

Bertie-Alvin is just shy of Category 4 status!

Actually, you have it a little low. 1KT = 1.15 MPH, so 100KT = 115MPH. The conversion from 10- to 1-minute is 1.14, so we're looking at 131.1mph

[P.K.]

Still no track image from Meteo France maybe I need to continue adding the points in Google Earth then.