Why JMA tend to tag invests too much?
Posted: Sat Jul 29, 2017 11:46 pm
They seem to do this in order to make WPAC scary. That's my opinion, i don't know what is the real answer for this one.
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Why JMA tend to tag invests too much?
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Re: Why JMA tend to tag invests too much?
Posted: Sun Jul 30, 2017 12:01 am
The JMA doesn't tag invests. It's the JTWC.
Re: Why JMA tend to tag invests too much?
Posted: Wed Aug 02, 2017 8:40 am
Re: Why JMA tend to tag invests too much?
Posted: Wed Aug 09, 2017 9:53 pm
To expound a little bit, JMA is the official RSMC agency for the WPac, so their tropical depressions, tropical storms, and typhoon numbers and data are all the official ones. JTWC is not an RSMC, but the way they present their data is consistent with that of the NHC and CPHC, which most users on this site are most familiar with. That includes designating invests. There is not any special requirements for an invest to be designated, and it's not unusual to see many of them fail to develop. The WPac sees many invests designated, but that is largely a function of the basin's overall activity. On average, over half of the Northern Hemisphere's ACE comes from the WPac, so a basin with lots of tropical cyclone activity is going to see even more invests that may or may not develop.
Going back to JMA, they actually have two different levels of tropical depressions. The first type is only analyzed on their surface map. JMA defines these fairly liberally, and these TDs are somewhat analogous to JTWC's invests. Their second type of tropical depression is generally closer to the classical tropical depression, and they designate these when they expect the to develop into a named storm and issue advisories on them. Again, JMA designates many tropical depressions of both types largely because of the overall elevated activity in the basin. Lots of disturbances are needed to develop lots of storms.
Going back to JMA, they actually have two different levels of tropical depressions. The first type is only analyzed on their surface map. JMA defines these fairly liberally, and these TDs are somewhat analogous to JTWC's invests. Their second type of tropical depression is generally closer to the classical tropical depression, and they designate these when they expect the to develop into a named storm and issue advisories on them. Again, JMA designates many tropical depressions of both types largely because of the overall elevated activity in the basin. Lots of disturbances are needed to develop lots of storms.
Re: Why JMA tend to tag invests too much?
Posted: Fri Aug 11, 2017 8:40 am
Yeah JMA uses 10 min so although not official, JTWC seems to be the most followed and discussed when a TC develops as they use 1 min similiar to NHC and CPHC. We can see that in the many different websites for following TC's over here and weather forums most notably storm2k and Weather Underground.
I guess it all depends on where you live. Here on Guam which is a U.S territory and all of Micronesia, we follow JTWC whereas the other countries in Asia possibly 3 mixed in. Their local weather agency, JMA, and JTWC to follow...
I guess it all depends on where you live. Here on Guam which is a U.S territory and all of Micronesia, we follow JTWC whereas the other countries in Asia possibly 3 mixed in. Their local weather agency, JMA, and JTWC to follow...