ATL: IRMA - Models

[tolakram]

GFS 12z run

[xironman]

Tropical storm warnings for Lake Erie.

[AxaltaRacing24]

Does anyone know if the adjustment techniques used by CFAN are actually increasing the forecast skill? According to Jeff Master's most recent post, the adjusted ECMWF operational run (red line) takes Irma right into southern Florida. The same scenario is shown by three of the five so-called "high probability clusters" (which are probably adjusted EPS members). However, the WSW movement in the Bahamas seems very suspect to me...

Source: https://www.wunderground.com/cat6/hurricane-irma-track-towards-lesser-antilles

It didn't work all that well with Matthew last year. Consistently showed more tracks over Florida.

If it weren't for that 30 mile E shift on Oct 6 we would have had the landfall though. But yes it was a bit too far west.

[Steve]

CMC full run also makes it up to Cleveland. It's uncanny close to the GFS from an overview perspective - just a bit farther south when it comes in but same end game. CMC has it transitioning over Cleveland where GFS stil has much tighter isobars.

CMC
https://www.tropicaltidbits.com/analysi ... 0&ypos=100

[Hurricane Andrew]

HWRF coming in stronger...now watching this with both eyes...

[stormreader]

Does anyone know if the adjustment techniques used by CFAN are actually increasing the forecast skill? According to Jeff Master's most recent post, the adjusted ECMWF operational run (red line) takes Irma right into southern Florida. The same scenario is shown by three of the five so-called "high probability clusters" (which are probably adjusted EPS members). However, the WSW movement in the Bahamas seems very suspect to me...

Source: https://www.wunderground.com/cat6/hurricane-irma-track-towards-lesser-antilles

It didn't work all that well with Matthew last year. Consistently showed more tracks over Florida.

If it weren't for that 30 mile E shift on Oct 6 we would have had the landfall though. But yes it was a bit too far west.

Yeah, well the whole thing with Mathew modeling was not something to write home about. Models were way too far east and the shift back west came relatively late in the forecast period. Don't know the time frame when you speak of tracks for Mathew over Fl, but hey, that was a lot closer than the operationals which clung to the hundreds of miles east of Fl for way too long.

[Bocadude85]

Between the CMC, the Euro, and the GFS this has all of the makings of Floyd part II. I still think the GFS is too far right in the mid term but the end result is relatively close.

Still 9-10 days out...how often does the GFS and CMC nail a 10 day forecast? The UKMET looks to be similar to the 0z Euro showing Irma heading into the Bahamas.

[Ken711]

CMC full run also makes it up to Cleveland. It's uncanny close to the GFS from an overview perspective - just a bit farther south when it comes in but same end game. CMC has it transitioning over Cleveland where GFS stil has much tighter isobars.

CMC
https://www.tropicaltidbits.com/analysi ... 0&ypos=100

Isabel like track.

[curtadams]

Oh wow. There's a curveball in the end game. A hook west as a strong tropical storm heading for Pittsburgh. Not every day can Pittsburgh say they're under a tropical storm warning!

All I know is how scary it would be to be sitting on the NE coast, watching a <900mb storm barrel northwards...is that even possible for a storm this far north? I mean..I can believe 920-940mb...but 890-900?

The GFS (or any global) is not tuned to handle the detailed internal dynamics of a tropical storm. The large size of Irma at that point could be inducing it to overestimate the pressure intensity, and this forecast should be read only as "should be very strong". For meaningful estimates of extreme pressures like what Irma will almost surely have we'll have to wait for the hurricane models to get out that far (but remember they tend to be bullish).

[Steve]

HWRF-P from 06Z is more or less in line. The difference between that run and last night is that it looks like Jose instead of following Irma actually makes a run for the Caribbean. Could be trouble down the way.

https://www.tropicaltidbits.com/analysi ... 0&ypos=100

[stormreader]

HWRF-P from 06Z is more or less in line. The difference between that run and last night is that it looks like Jose instead of following Irma actually makes a run for the Caribbean. Could be trouble down the way.

https://www.tropicaltidbits.com/analysi ... 0&ypos=100

Interesting Steve, could be lots of trouble down the line. Possible double whammy for the states.... This board will be lit up like a Christmas tree if that verifies.

[sma10]

I've been following GFS model runs since the GFS was born. Not to be flippant, but i literally have never seen an 8-9 day bullseye materialize (and trust me, many of those were catastrophic doozies).

I'm not an expert, but I do have considerable experience observing. I have been burned so many times by this model, I refuse to believe this scenario, even though it's repeated a couple times. If Irma does indeed make landfall it will almost certainly be someplace else (i.e. Florida, Cuba, Bermuda)

[GCANE]

12Z GFS.
The ridge over Ontario reappears, pushing back Irma for a later landfall.
Irma goes sub 900 mb for about 18 hrs in the eastern end of the Bahamas.

[Steve]

Also, I'd remind everyone to follow the MJO. The move into Phases 8, 1 and possibly 2 on the way back way way outside of the circle means a crazy pattern and a focus on the Western Hemisphere. FWIW, we moved into Phase 2 for Harvey.

We were talking about it during a lull in July. Absent a strong ENSO signal and with the very warm Atlantic, it seemed we could time at least a good percentage of tropical development based on the MJO this season. Problem is which runs to trust.

GFS Ensembles are bonkers with some of them wanting to go off the entire square.
http://www.cpc.ncep.noaa.gov/products/p ... ncpe.shtml

Australian model mean is a move back into Phase 2 but not as extreme as GFS Ensembles are into 8 and 1.
http://www.cpc.ncep.noaa.gov/products/p ... bomm.shtml

ECMF shows a weak signal inside the circle.

http://www.cpc.ncep.noaa.gov/products/p ... ecmf.shtml

[Hurricane Andrew]

HWRF is significantly stronger...note that we are still in the D8-D10+ range for US impacts...on the other hand, Irma will be crossing over the NE Caribbean islands in D4-D5...so we are getting closer.

[AxaltaRacing24]

I've been following GFS model runs since the GFS was born. Not to be flippant, but i literally have never seen an 8-9 day bullseye materialize (and trust me, many of those were catastrophic doozies).

I'm not an expert, but I do have considerable experience observing. I have been burned so many times by this model, I refuse to believe this scenario, even though it's repeated a couple times. If Irma does indeed make landfall it will almost certainly be someplace else (i.e. Florida, Cuba, Bermuda)

That's what I'm worried about. I'd rather the GFS wipe us off the map 4 times a day than miss us 4 times a day 5-10 days out.

[Steve]

I've been following GFS model runs since the GFS was born. Not to be flippant, but i literally have never seen an 8-9 day bullseye materialize (and trust me, many of those were catastrophic doozies).

I'm not an expert, but I do have considerable experience observing. I have been burned so many times by this model, I refuse to believe this scenario, even though it's repeated a couple times. If Irma does indeed make landfall it will almost certainly be someplace else (i.e. Florida, Cuba, Bermuda)

Agreed 100%. However, as bad as GFS and ECMWF have been in the mid-range this year in my opinion, we are now at about 8 days with GFS landfalling sometime in the Sunday Night-Tuesday AM time period. Anything can and will happen with the modeling between now and then. It's just so unfortunate that the 5-6-7 day runs have been whack, because that's where we're headed until Tuesday when we get to and probably inside of 5 days. It's watch the evolution of the models time for now.

[SouthFLTropics]

Between the CMC, the Euro, and the GFS this has all of the makings of Floyd part II. I still think the GFS is too far right in the mid term but the end result is relatively close.

Still 9-10 days out...how often does the GFS and CMC nail a 10 day forecast? The UKMET looks to be similar to the 0z Euro showing Irma heading into the Bahamas.

Slim to none...that's why we are so intently watching here on the SE FL coast. We still haven't had a landfall on the eastern side of the peninsula by any of the big models, save for ensembles. Quite frankly it's creeping me out.

[SouthFLTropics]

HWRF is faster...A full degree west of the 06z by 63 hours.

[SouthFLTropics]

Impressive...Most Impressive Indeed