ATL: HERMINE - Post-Tropical - Discussion

[Aric Dunn]

Classic case of "where the convection is" confusing some people. If you're looking at what would appear to be the main ball of convection, you could be forgiven for thinking it's tracking well into the Caribbean, south of PR and Hispaniola.

true in some cases. however last night it developed and was of course embedded in the convection. it then got spit out due to the low level flow.

[SFLcane]

 https://twitter.com/ericblake12/status/768442733648314368

[ScottNAtlanta]

It just needs to pop some convection over the center and it could be off to the races. Outflow, however, isnt nearly as good as it was yesterday

[jlauderdal]

Question: How significantly can land interaction change the center location or cause center reformation and
what effects if any could that have on the eventual track?

It depends. Sometimes it can help intensify (e.g. A perpendicularly landfalling storm in Texas). Other times it can rip a system apart ala mountains of Hispaniola or Mexico. A lot of times through the smaller islands, centers will want to stay over water and will hug or spin just off a coastline often going around even little jut outs. We are going to have to wait a few days to see what happens as it moves between where it is now and the Bahamas. To your question, there's no easy answer. Land interaction could do little, could influence the track some.

Personally, I do NOT believe that 99 is going to be wrestling with the high mountains in Hispanola. It looks like a clear shot to pass the island to the north, unlike some other developing systems from recent years. But considering the highest mountain there is just over 10,000 feet tall, that can (and has) disrupted or killed off many a storm in the past.

possible inflow issues even if it passes to the north but after that its smooth sailing all the way to the usa, could go through the straits/keys or the peninsula, ridging is strong(might not make it as far north as key west, trend has been south and west)...Bahamas land mass has zero effect on intensity, water is very warm as documented...our water temps(sofla) are 86-90(virginia key) so no issues there...keep in mind that if it goes across the everglades there could be little if any reduction with intensity...we saw this with katrina as it made the trip to the gulf...we haven't seen this potential in a long time with intensity and multiple landfalls..eric blake just reported 4mb pressure fall in st croix

[Blown Away]

Yeah I agree with you all where the LLC is, it is exposed and moving WNW and I think it could miss Hispaniola to the north if it keeps this heading. Vorticity is increasing as predicted by the ECMWF. The structure looks good so it seems if the shear lets up at some point in the next few days, this could take off.

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.

Seems the island terrain won't be a inhibiting factor in the development... About to enter high fuel SST's and we will see how the upper air environment will be... The more N this LLC gets, the more difficult it will be to miss Florida if it's going to the GOM...

[bg1]

That was the first test of the newer levee system (which btw are still only designed for a fast moving Category 3 here). Any Cat 4 or 5 or any massive storm surge from a lower-cat storm (Katrina) would still inundate the city.

This worries me, since isn't one of the models seeing a large Cat 3 into LA?

[Chris_in_Tampa]

what time do they take off?

11am EDT I believe.

Any moment. Plane is sending obs from the ground. They should arrive by 11am EDT.

[Aric Dunn]

on a side note.. we dont have to worry about ex fiona interacting as there is zero of it left so the models that continue to show that scenario are clearly wrong.

[Weatherboy1]

Personally, I think they probably should give 99 a TD designation at 11 a.m. but they might wait a bit longer to A) get confirmation of an LLC from recon and B) make sure the "slightly naked swirl" doesn't blow itself apart. It seems to me that 99 looks better now than Fiona did for a while toward the tail end of her life as a designated system.

[Weatherboy1]

on a side note.. we dont have to worry about ex fiona interacting as there is zero of it left so the models that continue to show that scenario are clearly wrong.

Agreed. I didn't understand why some models insisted on her doing anything in terms of re-intensification.

[Aric Dunn]

what time do they take off?

11am EDT I believe.

Any moment. Plane is sending obs from the ground. They should arrive by 11am EDT.

we will be getting direct data from the inner part of the circ the moment they take off since they are literally stationed in it.

[Steve]

That was the first test of the newer levee system (which btw are still only designed for a fast moving Category 3 here). Any Cat 4 or 5 or any massive storm surge from a lower-cat storm (Katrina) would still inundate the city.

This worries me, since isn't one of the models seeing a large Cat 3 into LA?

If you want to be worried, go watch Joe Bastardi's video this morning. It's the usual bit of hype, but if I heard him right, he's got this:

Ramping up in the Bahamas right up to South Florida probably hitting as a Hurricane. He drew the parallel to what Katrina was like in South Florida.

Bulls eye after that is Louisiana as a major. The Weatherbell "window" was drawn about from Corpus Christi over to South Alabama focused on LA though he said he's also worried about a farther west scenario toward the Upper Texas Coast (SE Texas).

I'm still not sold on any solution at this point, because there are variables 7 days out that no one can usually even predict. For all we know the GFS could be right or aliens could attack or they could resume trials of Dynomat to try to knock this thing back. But like I said, I'm going to grab some supplies now so I don't have to deal with anything this weekend or early next week other than evacuating or deciding to hunker down.

[Nederlander]

That was the first test of the newer levee system (which btw are still only designed for a fast moving Category 3 here). Any Cat 4 or 5 or any massive storm surge from a lower-cat storm (Katrina) would still inundate the city.

This worries me, since isn't one of the models seeing a large Cat 3 into LA?

EURO showing what looks like a Cat 4 to the TX/LA border, GFS showing a weak system turning quick to the north along the FL west coast... and the CMC showing a weak system into NOLA..

[Blown Away]

Personally, I think they probably should give 99 a TD designation at 11 a.m. but they might wait a bit longer to A) get confirmation of an LLC from recon and B) make sure the "slightly naked swirl" doesn't blow itself apart. It seems to me that 99 looks better now than Fiona did for a while toward the tail end of her life as a designated system.

Once/if 99L becomes a TD/TS, SFL will likely be in the 5 day cone...

[BigB0882]

I will begin feeling better (barely) if we get two more runs from the Euro with west tracks, taking this into central Texas if possible. That would tell me that they are still trying to break that ridge down too soon which was my initial fear. I thought at first that they would break it down too soon and it would end up in Louisiana but now it appears they might have been underdoing it even more than I thought and it could miss us to the west completely. At least, that is now my hope.

My big fear is they have shown a Florida big bend hit, a TX hit and will now begin to focus in on the middle ground.

[msbee]

Sint Maarten, Netherlands Antilles
Princess Juliana International Airport
latitude: 18-03N, longitude: 063-07W, elevation: 4 m
Current weather observation
The report was made 36 minutes ago, at 13:16 UTCWind 13 kt from the East/Southeast with gusts up to 33 kt, varying between East and South/Southeast Temperature 27°C Humidity 89% Pressure 1012 hPa Visibility: 2000 m Broken clouds at a height of 1100 ft, Towering cumulus.
Scattered clouds at a height of 3500 ft heavy rain showers

[ScottNAtlanta]

Just an fyi...systems that go north of Hispaniola are not as adversely affected as those that go south. The southerly track pulls drier air down sloping while a northern track does not

[MGC]

Unless that naked swirl builds some convection it will likely spin down. It has a good bit of shear over it. Still betting the MCL builds down to the surface eventually.....MGC

[ScottNAtlanta]

Unless that naked swirl builds some convection it will likely spin down. It has a good bit of shear over it. Still betting the MCL builds down to the surface eventually.....MGC

I'm thinking its more mid level dry air than shear. The sat loops show west to east movement north of 99L not out of the north.

[Ntxw]

Quick reminder folks since the board will likely get busier in the coming days. I've had to edit some posts quoting images. Please take a few moments if you are quoting another post with an image to remove the IMG tags ([IMG]). I know its an extra step but we don't need to see the same images over and over again especially when there is a high quantity of posts coming.

Thanks for the help!