ATL: HERMINE - Models

[rockyman]

Joe B. is forecasting a major Cat.3 strike on North Carolina this is why.

 https://twitter.com/MJVentrice/status/768081797733318656

That's basically the 0z Euro shifted to the east.

[gatorcane]

The latest HWRF and ECMWF looks in pretty close agreement on where this will be in 5 days. ECMWF shows a west then south of due-west turn into South Florida. It actually is more to the right (east) of the HWRF before the turn. HWRF doesn't go out far enough to know what it would do as far as Florida impacts but it seems to be turning it west also at the end also.

Personally I would bet on a ridge over the Carolinas being there with some kind of west turn.

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.

[Javlin]

My biggest concern at the moment is that the models will continue to see that ridge being strong and not breaking it down soon enough. That ridge has been persistent all summer so will it break down next week? I tend to doubt it. I also know models often underdo the ridges as you get beyond 3-4 days. Right now Louisiana would be saved as the models show this turning sharply north once in the Gulf but what if that turn is much more gradual or happens later? I can't imagine what this area would do. Has an area ever been hit by multiple natural disasters in a short period of time? I know someone mentioned 3 hurricanes hitting a rather small area in 1860 but of course you did not have the populations we have now.

I mentioned that as I was reading up on the impact of storms along the coast.It occurred overa 3-4 week span been years since I read it but was in a 120 nautical mile range in the extremes maybe like from LA/MS to Pensacola just as a reference the pattern was in place.We have had two thus far at the LA/MS line in the last few weeks just my concern.JMA still showing the UL in the NE but no break in the ridge.The CMC shows the break and you got to wonder who knows Canadian's weather? It's just the low exiting in the NE just does not seem to be having as much effect on the tropics in the Caribbean?

[TheStormExpert]

The latest HWRF and ECMWF looks in pretty close agreement on where this will be in 5 days. ECMWF shows a west then south of due-west turn into South Florida. It actually is more to the right (east) of the HWRF before the turn. HWRF doesn't go out far enough to know what it would do as far as Florida impacts but it seems to be turning it west also at the end also.

Personally I would bet on a ridge over the Carolinas being there with some kind of west turn.

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.

The ridge being over the Carolina's is a real possibility but one cannot disscount the latest 00z Euro Ensembles actually showing 99L heading straight for the Carolina's.

[WeatherEmperor]

I would not be surprised if the models shift a bit further east. We have seen many systems in years past that pointed at Florida because of a strong ridge...only for that perfectly timed weakness to show up out of nowhere turning them north to the Carolina's for example. I think we need another 2-3 runs to show a solid ridge before the likelyhood of a Florida strike become very high. For now, I am just watching and waiting

[TheStormExpert]

I would not be surprised if the models shift a bit further east. We have seen many systems in years past that pointed at Florida because of a strong ridge...only for that perfectly timed weakness to show up out of nowhere turning them north to the Carolina's for example. I think we need another 2-3 runs to show a solid run before the likelyhood of a Florida strike become very high. For now, I am just watching and waiting

I agree, there is always something that swings through to bresk down these ridges epecially as we head into late August and September.

[Steve]

I would not be surprised if the models shift a bit further east. We have seen many systems in years past that pointed at Florida because of a strong ridge...only for that perfectly timed weakness to show up out of nowhere turning them north to the Carolina's for example. I think we need another 2-3 runs to show a solid run before the likelyhood of a Florida strike become very high. For now, I am just watching and waiting

I agree, there is always something that swings through to bresk down these ridges epecially as we head into late August and September.

This is not true. Had you said "sometimes" okay. But not "always" and especially not even usually in late August.

[tolakram]

Stop the back and forth please. Keep the discussion about model runs and NOT opinions on what might happen.

[TheStormExpert]

Would be nice if we could get a G-IV synoptic flight out to 99L to put an end to these model swings.

[Ntxw]

Repost, we should avoid clutter of opinions here. Readers don't need to go back and forth between the discussions and model threads for the same things. Lets reserve this thread for posting model graphics, data, and information relating to guidance. It's fine to state your thoughts on a particular model or model run but try to include the actual model run so that we can keep things technical.

FYI,

I am deleting off topic posts. I will repost what I said earlier.

The idea of the model thread is a place to hold saved model graphics (no direct image links please) and discussions or questions pertaining directly to a model run. One liners, random thoughts, and other posts will be removed to try and keep these threads strictly on topic and more useful in the future when looking back at a storm and model performance. Please understand that the desire is not to squash conversation but to keep these threads very technical in nature. If you have doubts about a post then the discussion thread is probably the best place to put it.

Thanks for your cooperation.

[gatorcane]

12Z NAM to see the steering pattern. Big ridge over the SE US is sliding slowly east over the Carolinas at 84 hours:

[Steve]

The only game in town this time of day is the NAM. It doesn't do much with the remnants of Fiona which it has fading out at the end of the run (84 hours or 3 1/2 days) and 99L (Hermine apparently or close to it at 850 mb) moving just north of the coast of Hispaniola and then moving into the southern Bahamas. Looks about right though there is a leading piece of energy that drops down to the Yucatan area also at 850mb. I still think ALL the models are having some issues with potential split energy and too many systems in close proximity at one time. With the HWRF 06z progs on Lionrock still sort of stalled out but SE of Japan and possibly moving out, the buckling of the Jetstream isn't likely to be quite as extreme as was being forecast yesterday. That ups the game for the Atlantic Coast IMHO.

[GeneratorPower]

Above poster has a good point about too many things in the same place at the same time. With any model or forecast, the more complex, the more likely it is that some factor isn't well modeled and won't behave as expected.

[Ntxw]

Above poster has a good point about too many things in the same place at the same time. With any model or forecast, the more complex, the more likely it is that some factor isn't well modeled and won't behave as expected.

There are definitely moving parts. All the guidance generally do agree there is strong ridging in the Carolinas as the system approaches the Bahamas. And generally even the ensembles and OP guidance they do agree the ridge will break down in the later term of their runs. It's that gray area in between just before this happens that 99L squeezes into.

Generally agree on the ridge from the EPS



Pattern shift gradually occurs, weakening of the ridge. Where is 99L between these stages in terms of speed and strength is the question

[BobHarlem]

Joe B. is forecasting a major Cat.3 strike on North Carolina this is why.

 https://twitter.com/MJVentrice/status/768081797733318656

That's basically the 0z Euro shifted to the east.

This is a bit weird considering the 500mb heights of the system, I'm not sure I'd trust this one (the model output).

[gatorcane]

GFS vs the ECMWF - epic battle with huge implications as far as impact. Looking forward to the upcoming runs to see which one caves is as they both can't be right.

[GeneratorPower]

GFS vs the ECMWF - epic battle with huge implications as far as impact. Looking forward to the upcoming runs to see which one caves is as they both can't be right.

It's so hard to discount the ECMWF with both the 12Z yesterday and 00z today runs being fairly consistent.

[rockyman]

12z GFS is running.

http://www.tropicaltidbits.com/analysis ... 0&ypos=513

More defined through 30 hours (closed isobar over Puerto Rico)
Looks like it's going directly over Hispaniola between 36 and 42 hours

[chris_fit]

Almost looks like Erin of last year on the latest GFS - right over hispaniola - The Shredder

[rockyman]

GFS takes it right over Hispaniola @ 42 hours...

Edit: Sorry.. Didn't see your post ^^

Then appears to reform off the north coast of Hispaniola in 48 hours