JMA vs JTWC

[cycloneye]

I dont know a lot about the Western Pacific,and that is why I have a question about why there is a spread in terms of the intensity between what the Japan Meterological Agency says and what the Joint Typhoon Warning Center says.For example JMA says that the typhoon now in the Western Pacific has 90kts but JTWC says it has 115 kts.Why that discrepancie?

[senorpepr]

JMA uses the world-wide standard of 10-min average winds. JTWC uses the American standard of 1-min average winds. That usually accounts for most of the discrepancies.

For instance 90KT (10-min avg) by the JMA roughly equals 103KT (1-min avg) by the JTWC.

Now, the remaining difference is usually do to difference in "science." JTWC relies heavily on Dvorak estimates to base their wind speeds. JMA takes other items into account. Basically, it boils down to different "rules of thumb."

[cycloneye]

Thanks Mike for clearing this up to me and for sure to other members.