ATL: MATTHEW - Post-Tropical - Discussion

[wxman57]

My biggest problems with the models is that the 240 hour position of the lastest EURO & GFS is over 1000 miles apart. One of these models is going to be horribly wrong... Im not sure which one it will be, but one would think that we need to see these two models come to a better agreement before we can really come to any conclusions on a potential USA threat.

Both of them are likely to be wrong. We're not sure when the storm will be picked up and steered northward. Very high uncertainty beyond 4-5 days, like with Joaquin last year.

[cycloneye]

 https://twitter.com/TropicalTidbits/status/780775726832291840

[SFLcane]

Sorry folks this isn't blowing up into a cat3-4 into Haiti as the GFS showing I think it's more gradual as the ECMWF is showing. Shear will be an issue next couple of days.

[TheDreamTraveler]

Here's Levi Cowan's video from lastnight in case anyone missed it. Some interesting discussion.

https://www.youtube.com/watch?v=WK6y7JkrLLs

[toad strangler]

It's times like this when models and ensembles are jumbled up when I look at climo. Not for a forecast, but a general idea of where historically areas are in play. While we wait this out I'm looking at a blend of Sept and Oct ...

[cycloneye]

 https://twitter.com/MichaelRLowry/status/780769845415731202

[KWT]

My best guess is they find enough to classify it. Seems to be it'll happen at some point in the next 24hrs regardless of what recon finds.

I'm also in the slightly slower development camp, still likely hurricane but more on the ECM timescale rather than the aggressive GFS one.

PS, as for why this board isn't busy yet...early days and we've just come off the back of a couple of days of 'us no hit' on the models, now they coming back west watch the board light up...sad but true!

[tolakram]

Convection increasing.

http://weather.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20NHE&lat=17&lon=-54&info=vis&zoom=1&width=1024&height=600&type=Animation&quality=92&palette=ir1.pal&numframes=8&mapcolor=yellow

[tolakram]

saved rgb

[Steve]

toad,

Climo can help, but would you not agree that we're not in a typical late September type pattern? There's a front and a cutoff low coming into the picture, but those will be replaced. Water is still too warm in the Gulf and Western Atlantic to allow for fall to take hold in the South.

In my opinion, the threat to the US is increasing. We have a legitimate model like the European and tropical models HWRF and GFDL setting up a bad scenarios for Florida and/or the Gulf of Mexico. HWRF is a bit east of Jamaica while GFDL comes in south of Jamaica on a more westerly heading. Bastardi says their forecast is for it to come up into the Gulf before turning North. He has a blend of different storms he's been talking about including some that hit FL, Gulf and US East Coast.

I said I didn't think we would know much before this weekend. It could be even Monday or Tuesday next week. But I think the threat for a landfalling major isn't really bogus 10 day speculation at this point. I think the threat is real though we all know one can never be sure in the tropics. I'd currently put the odds of a hurricane hit on the US or Bahamas somewhere around 80%. I think the threat of a major (or a fading storm that was a major) is at least 50%.

Here's what I'm going to be watching. The WPAC teleconnection holds up if the ECMWF is right. Megi will landfall later today in China a little farther north than JTWC was predicting (noted that the GFS did have it crossing Taiwan farther north than JTWC had it). Ridging will be along the US East Coast in 7-10 days which is the middle to end of next week. So how fast does Matthew come across the Caribbean? Some are saying it will slow down maybe even to a stall or crawl for a while. And does a trough follow the second high that builds in after the cutoff low or is that just a slower pattern as well?

Early warning is for everyone from the Northern Gulf over to New England to handle up supplies this week. By the weekend, this could be big news in Florida, and you know there's going to be a mad rush and panic. Everyone else can probably wait until the weekend, but if you happen to be at the store, pick up a couple extra cases of water, batteries and supplies. They're going to be in short supply in a lot of places next week.

[leanne_uk]

We have some building work going on at my Mother in Laws house in Grenada....
I gather as the centre appears to be slightly more north than Grenada's lattitude that they will be in the clear?

Well in the clear with regards the worst of any weather.

[Bocadude85]

My biggest problems with the models is that the 240 hour position of the lastest EURO & GFS is over 1000 miles apart. One of these models is going to be horribly wrong... Im not sure which one it will be, but one would think that we need to see these two models come to a better agreement before we can really come to any conclusions on a potential USA threat.

Sorry to pick on you here, it's meant more of a discussion, but why on earth even look at the 240? We know for a fact the verification at this range is extremely low, especially for a single feature. I think it's usable to try and get some information on overall patterns but for a tropical system, to see much past 120/144 hours as more than entertainment is folly. In my opinion, of course. AS models improve you might add another day to the dependable range but it will be a long long time before 240 is accurate.

One other thought. We know globals are pretty bad at estimating intensity, so if the intensity of a storm will be a driving factor in the track then a model can make a much bigger mistake than usual if it gets the intensity wrong. It might nail the upper air environment in 5 days but still fail in predicting the location of a tropical storm.

I agree that the 240 hour forecasts are pure fantasy but the sheer difference in location is noteworthy in my opinion. The Euro still has this in the Caribbean while the GFS has it onshore in the Northeast. I mean even the 144 hour positions are 300-400 miles apart.

[Weatherboy1]

Really this far out it's impossible to narrow down a specific landfall target. But it does appear that the models, on balance, have shifted somewhat further west over the last 24-36 hours. It'll be interesting to see if that trend continues. What worries me is that there's the potential for significant strengthening in the Central/Western Caribbean if 97 gets there and if he can stay far enough away from the South American coast. So definitely watching and waiting here in South FL!

[Fishing]

Well fwiw , our local met here in Charleston,SC just said "well you know how much I rely on the European mod , I really fee like this is going to be more of a Gulfcoast threat".

[RL3AO]

It'll probably get sheared a bit over the next day or two by those southerlies coming off Venezuela, but they've been weakening and shifting from the SW to the S to SE (less shear). So yes some shear, but currently helping more with outflow than hindering it.

[Rail Dawg]

This was a hot September for us here in Houston.

Almost every day we were seeing temps in the mid 90's and up.

Summer does not end until September here but this year was especially warm and drawn-out.

Very muggy last night.

Lots of energy out there still.

[Alyono]

SHIPS has low shear through 5 days

[LarryWx]

IF this is declared a TD by 55W and if it later hits the CONUS, this would then become the only TC on record that hit the Conus after forming east of 55W after 9/25.

I'm not entirely sure on the accuracy of this claim. I mean, I know that it's true based on historic records, but I'd be willing to bet that some of those land-falling storms would've been classified east of 55W if we had the same technology we do today. And anyway, I generally dislike broad statements like that, because they're just too generalizing of something as complex as the atmosphere. Basically, I don't think it really matters if it forms east or west of 55W after such and such date, but I still think it'll be interesting to see if it does break that "record."

That is a good point about one or more conus hitting storms likely forming east of 55W after 9/25 but being missed largely due to lack of technology if we go back far enough. Even if somehow none did since 1851, this is a "record" waiting to be broken imo, especially within just a few days after 9/25 and just east of 55W like may be the case for 97L as it looks like a conus threat. I'm not looking at whether or not it forms by 55W as making a difference when it isn't that far from 55W and we're only two days after 9/25. Then again, there have been none on record (though one or more still could have been missed) during the ~55 year long satellite era. So, climo still tells us this would be an extremely unusual occurrence in any one year. Regardless, I do think the chance of 97L hitting the conus is up there pretty high.

[Hurricaneman]

This is heading almost due west looking at visible, what people are seeing heading more WNW might be the MLC which means there is some mid level shear impacting this but not more than 15kts

BTW the center is around 52.5W 12.8N

[PTrackerLA]

FWIW JB's forecast is essential the 00z Euro ensemble mean takes a cat 4 into the Gulf with a turn towards the north central gulf coast. He's typically overly bullish but wow.