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#1481973 - 21/12/2018 11:36 Re: FV3-GFS [Re: ashestoashes]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 945
Loc: Pinjarra Hills, Qld
I thought one of the changes with FV3 was that the unrealistically deep minimum lows forecast by GFS would be improved. Some have commented that FV3 may have gone too far to the opposite extreme and not allowing enough formation of deep lows. We saw with TC Owen that FV3 deviated significantly from GFS.

Well now look at what FV3 has cooked up in the 20 Dec 12Z run at about 300 hours onwards, a deep low NE of New Caledonia, when the 12Z run and forecast hours from GFS are much more moderated.
http://www.pivotalweather.com/model.php?m=gfs_fv3&p=sfcwind_mslp&rh=2018122012&fh=324&r=au&dpdt=

Before anybody says it, I do acknowledge that anything beyond about forecast 96-120 hours can often be quite speculative.

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#1490486 - 15/02/2019 16:07 Re: FV3-GFS [Re: ashestoashes]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7863
Loc: Maryborough, Wide Bay, QLD

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#1490488 - 15/02/2019 16:20 Re: FV3-GFS [Re: Mega]
Ken Kato Offline
Meteorological Motor Mouth

Registered: 05/03/2012
Posts: 6069
That's about the only advantage of our region not regularly getting large amounts of snow laugh

If we did, it'd be a problem but from the many comparisons I've made between FV3 and current GFS for rainfall amounts and placement in our region, I've found the FV3 has been far superior to GFS especially in terms of not putting in the unrealistically intense precip bullseyes all over the place.
But that's for short range rainfall forecasts (24hrs or less) so I'm not sure if the same level of better skill applies to longer range forecasts for our region.

One thing I will say though is that I still have reservations about how well the FV3 does with tropical systems in the Australian region and their associated heavy rainfall. I'd prefer to make more comparisons before I can draw any conclusions from that aspect of it.

The FV3 was originally due to become fully operational on the 29th Jan but the government shutdown interfered with that (at least all parties were given ample warning of that though).

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#1490490 - 15/02/2019 16:32 Re: FV3-GFS [Re: Ken Kato]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 945
Loc: Pinjarra Hills, Qld
Originally Posted By: Ken Kato

One thing I will say though is that I still have reservations about how well the FV3 does with tropical systems in the Australian region and their associated heavy rainfall. I'd prefer to make more comparisons before I can draw any conclusions from that aspect of it.

Agree. I have been looking at it for a while but not done any objective fair comparisons. But what I have seen does not inspire confidence. frown
_________________________
Models are for estimating and gauges are for knowledge.

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#1490497 - 15/02/2019 17:00 Re: FV3-GFS [Re: Flowin]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7863
Loc: Maryborough, Wide Bay, QLD
Originally Posted By: Flowin
Originally Posted By: Ken Kato

One thing I will say though is that I still have reservations about how well the FV3 does with tropical systems in the Australian region and their associated heavy rainfall. I'd prefer to make more comparisons before I can draw any conclusions from that aspect of it.

Agree. I have been looking at it for a while but not done any objective fair comparisons. But what I have seen does not inspire confidence. frown


It's been worse than GFS, hands-down.

And this is just my opinion, but GFS splattering convective rainfall all over the place is a pretty small price to pay if in the end the model is still overall more accurate for our part of the world. Some of the FV3 solutions I've seen over the past few months have been mind-boggling to say the least and it makes you wonder how it's so close to release.

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#1490499 - 15/02/2019 17:11 Re: FV3-GFS [Re: Mega]
Ken Kato Offline
Meteorological Motor Mouth

Registered: 05/03/2012
Posts: 6069
Originally Posted By: Mega
And this is just my opinion, but GFS splattering convective rainfall all over the place is a pretty small price to pay if in the end the model is still far more accurate for our part of the world.

Dunno which model you were referring to by "the model" but personally, I'd much rather prefer the FV3 for Australia than GFS (but mainly for precip for short range forecasts) since rainfall amounts and placement are one of the vital bread and butter variables we need to routinely forecast here compared to high snowfall amounts. The extreme rainfall bullseyes that current GFS puts down are a pain and they also have flow-on effects such as increasing the model-averaged rainfall amounts in products like WATL rainfall and OCF.

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#1490504 - 15/02/2019 17:27 Re: FV3-GFS [Re: Ken Kato]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7863
Loc: Maryborough, Wide Bay, QLD
Originally Posted By: Ken Kato
Originally Posted By: Mega
And this is just my opinion, but GFS splattering convective rainfall all over the place is a pretty small price to pay if in the end the model is still far more accurate for our part of the world.

Dunno which model you were referring to by "the model" but personally, I'd much rather prefer the FV3 for Australia than GFS (for things like precip for short range forecasts) since rainfall amounts and placement are one of the vital bread and butter variables we need to routinely forecast here compared to high snowfall amounts. The extreme rainfall bullseyes that current GFS puts down are a pain and they also have flow-on effects such as increasing the model-averaged rainfall amounts in products like WATL rainfall and OCF.


That is a good point and I can't argue with it at all. It will at least (hopefully) help clean up those silly bulls-eyes during big storm events. However, I was under the impression that FV3 did this by reducing the convective feedback for large storm clusters like tropical lows etc. From what I've seen it hasn't done that at all, and theoretically speaking, you'd think that issue would carry through to our part of the world in the sub-tropics during big storm events too.

The other thing is that I guess I'm just not convinced FV3's issues lie only on tropical activity through the Australian region. While it might end up being in the okay short-term, I've seen nothing yet to convince me it's any better in the mid to long-range unfortunately. This winter and '19 spring/summer will be a good test for it so hopefully it proves me wrong.

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#1490507 - 15/02/2019 17:35 Re: FV3-GFS [Re: ashestoashes]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 945
Loc: Pinjarra Hills, Qld
For TC and TS weather events, I prefer HWRF but it only goes out to 120 hours. The range of detailed outputs is also much more useful like the Wind swath and rain swath.

Ken do you know if they have ever run HWRF longer than 120 hours, or plans to extend its lead time ?

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#1490526 - 15/02/2019 18:16 Re: FV3-GFS [Re: ashestoashes]
Ken Kato Offline
Meteorological Motor Mouth

Registered: 05/03/2012
Posts: 6069






Flowin: Note sure if they've ever run it out past 126hrs and I also don't know of any immediate plans to extend it beyond 126hrs either.

Mega: Its skill in the longer range depends on what parameter you're looking at and how you measure it really. For example, the above graphs are for anomaly correlation (one of the most common and widely used forms of statistical analysis of model skill) for MSLP in the southern hemisphere (1st graph) and the global tropics (2nd graph). They show the natural die-off in skill with forecast lead time. The higher the better using that particular skill measuring technique.
I don't believe anyone's done any objective skill analyses specifically for the Australian region yet though, let alone any QPF skill scores for our country. Once it becomes fully operational for awhile, it might be done.

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#1490781 - 18/02/2019 07:40 Re: FV3-GFS [Re: ashestoashes]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 945
Loc: Pinjarra Hills, Qld
I noticed this morning that the FV3 model is now available on Meteologix. Good to have some access to it on a page where the map area can be changed.

https://meteologix.com/au/model-charts/gfs/1602-e-268-s/sea-level-pressure/20190217-2100z.html

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#1497341 - 09/04/2019 20:54 Re: FV3-GFS [Re: ashestoashes]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 945
Loc: Pinjarra Hills, Qld
So it has now been a few more months with USA next generation GFS model "FV3" in the mix of available forecasts.
In Aus area there have been a few cyclone near misses, actual landfall crossings, ocean residuals that have occurred over such time as well as a prolonged near stationary monsoon trough causing the late jan and early feb period of flooding in NQ.
I have not tracked model performance for FV3, but often looked at in mix of available model forecasts. Seems to me FV3 carries some traits of GFS with deep lows.
_________________________
Models are for estimating and gauges are for knowledge.

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