ATL: IRMA - Models

[NDG]

Wind gusts forecast by the 12z Euro.

mph?

Yes.

[Blown Away]

Updated spaghetti. Note EURO not shown (west of the tightly clustered guidance) and similar to the UKMET as it comes into the Keys from the south:

Wow, hard to discount that tight cluster, but the Euro is King... Glad I'm not making track decisions...

[CaptinCrunch]

NAM and UMET are close to the EURO

[NDG]

Wind gusts forecast by the 12z Euro.

What could we expect in Palm Beach Gardens (just north of West Palm Beach)?

Is showing wind gusts in the 100-110 mph.

[CaptinCrunch]

Harvey made landfall with 135 mph sustained winds at the EW, Irma will be stronger at Landfall.

[ozonepete]

the cone will shift. that is your best model, and its moved significantly west. Even if you split the difference. Its still way west

The cone and the track are based on so many models that even a specially added weight to the Euro would not shift the track back west noticeably. It's also starting to be the only model that far west so it's hard to see them adding weight to it.

[Steve]

skufful,

It makes complete sense. Sorry to anyone else who's seen me post about this since last week, but the biggest player in the game was always going to be high pressure coming down from Canada. It is the reason that everyone was asking why Irma went NW and WNW once inland vs. NE or ENE out. The reason was the retreating trough would be replaced by high pressure seeping/oozing down from the north which would create an umbrella situation where there was high pressure to the NE, N and NW of Irma as it was inland. 06Z models this morning that were biased east (NAM, GFS) started to show the retreating trough ahead of the high pressure coming down smaller and farther east.

The best way I can explain it because I'm a completely lay person is to remember that high pressure flows clockwise. The Canadian high is at the surface, but it's also aloft except to the west where the small shortwaves/upper lows are embedded and coming down from Montana like Aric was talking about on Sunday or Monday.

Red is High Pressure on the EC Height Anomalies:
https://www.tropicaltidbits.com/analysi ... 0&ypos=558

^^ That run is at 500mb or approximately 18,000 feet or just over 3 miles up. That's not terribly high - say about halfway to where the jets usually fly. But it's generally a good indicator of synoptics.

Now if you look at the 200mb stream flows which is around 39,000 feet (roughly 7.4 miles up), you will see the higher up setup and stream flow. I'm not necessarily implying that Irma will be guided at the 200mb level. But you can see where the weather is going. For this run, we'll have to use the Canadian 200mb winds since Tropical Tidbits doesn't get the 200mb on the EC. The CMC won't be exactly right, but it's close enough to make the point.

https://www.tropicaltidbits.com/analysi ... 0&ypos=310

Let me know if this doesn't make sense to you and I'll try to clarify it.

[SEASON_CANCELED]

Harvey made landfall with 135 mph sustained winds at the EW, Irma will be stronger at Landfall.

I think the fact that harvey stalled was the bigger issue. The winds did not do an insane amount of damage proportional to the flooding. I dont see rain being a huge factor with this one. Most of the models show it zipping up the state at a good clip but those winds are going to be inland and you have alot of rural old country that is going to get creamed.

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

[JPmia]

The EURO's latest run will just shift their track a little to the left of the last point, which will most likely be directly over SE FL again and possibly have the eastern eyewall over the metro areas. Indeed, worst case scenario. In fact, when the State EOC does their hurricane drill every year, this track is in general their worst case scenario.

[skufful]

skufful,

It makes complete sense. Sorry to anyone else who's seen me post about this since last week, but the biggest player in the game was always going to be high pressure coming down from Canada. It is the reason that everyone was asking why Irma went NW and WNW once inland vs. NE or ENE out. The reason was the retreating trough would be replaced by high pressure seeping/oozing down from the north which would create an umbrella situation where there was high pressure to the NE, N and NW of Irma as it was inland. 06Z models this morning that were biased east (NAM, GFS) started to show the retreating trough ahead of the high pressure coming down smaller and farther east.

The best way I can explain it because I'm a completely lay person is to remember that high pressure flows clockwise. The Canadian high is at the surface, but it's also aloft except to the west where the small shortwaves/upper lows are embedded and coming down from Montana like Aric was talking about on Sunday or Monday.

Red is High Pressure on the EC Height Anomalies:
https://www.tropicaltidbits.com/analysi ... 0&ypos=558

^^ That run is at 500mb or approximately 18,000 feet or just over 3 miles up. That's not terribly high - say about halfway to where the jets usually fly. But it's generally a good indicator of synoptics.

Now if you look at the 200mb stream flows which is around 39,000 feet (roughly 7.4 miles up), you will see the higher up setup and stream flow. I'm not necessarily implying that Irma will be guided at the 200mb level. But you can see where the weather is going. For this run, we'll have to use the Canadian 200mb winds since Tropical Tidbits doesn't get the 200mb on the EC. The CMC won't be exactly right, but it's close enough to make the point.

https://www.tropicaltidbits.com/analysi ... 0&ypos=310

Let me know if this doesn't make sense to you and I'll try to clarify it.

Thank you for your response, I will study on it.

[RL3AO]

The 12z Euro gives me more confidence about the NHC being pretty close to correct. Near worst case scenario for Miami.

[tgenius]

Irma is expected to pick up forward speed when she goes north right? Trying to roughly calculate how long we will be in hurricane force winds time wise.

[NDG]

12z Euro Simulated Radar forecast of Irma.

[tolakram]

I have locked this topic temporarily.

Some people are posting questions that belong in the discussion thread, please post there and not here, this thread is for model discussion only.

[Dean4Storms]

Does anyone know if the models actually take into account that a Storm center moving over the Everglades is actually moving over warm water?

[chris_fit]

12Z Euro Ensembles

[Steve]

Based on those ensembles, it's very possible that the ECMWF Operational could move back a shade toward the Eastern Keys Southern tip of the Peninsula from the Western and Central Keys at 00Z. Majority of tracks look like the JMA 12Z staying inland (as did the EC operational at 12Z once it landfilled) but probably coming in on an angle from slightly farther east to begin with. If so, that's slightly better news for the West Coast of Florida. If not, well they're getting smacked too. We'll be within about 60 hours until landfall for the 00Z models validity time (8 Eastern, 7 Central). Model verifications will continue to get better and better as we move closer to landfall.

['CaneFreak]

Can anyone explain why the westward shift with the models? Is it just a weaker shortwave diving in from the Lower & Mid-MS Valley and a stronger Bermuda/Azores high or what seems to be driving this change?

[RL3AO]

Does anyone know if the models actually take into account that a Storm center moving over the Everglades is actually moving over warm water?

Yes. Land use is accounted for in all models. It's why the Euro and gfs actually forecast urban heat islands.

[otowntiger]

The 12z Euro gives me more confidence about the NHC being pretty close to correct. Near worst case scenario for Miami.

Agreed- it's almost like an anchor keeping the official track from shifting east. It is kinda counteracting some of the tugs to the east but not weighty enough to pull it back west at all in my opinion.