ATL: FLORENCE - Post-Tropical - Discussion

[drezee]

I personally think she will go Cat 5 at some point in the next 36 hours. The environment is ready for it. It is not sustainable though. The recon may not be there to measure it. I think it will be a 6-10 hour period only.

[Maryellen46]

I hope people listen to the warnings.... it's easy to dismiss when you have had previous storms that come in weaker than expected, but this is the real deal. I hope people are listening.

And if she stalls, some areas could see up to 40” of rain.

[FLpanhandle91]

I do believe Florence will shed the cloud tops to her west and we should see a very symetrical CDO emerge as she transitions to an annular hurricane this evening.

[supercane4867]

[Steve]

I do believe Florence will shed the cloud tops to her west and we should see a very symetrical CDO emerge as she transitions to an annular hurricane this evening.

Do you really think it's going to go annular? That's not something we see very often, even with Cat 5's. None of the models, including the hurricane models, are showing that kind of depiction. I'm not saying that it can't happen, but it doesn't seem likely unless you know something I don't. And if so, I'm all ears.

[Dean4Storms]

Note that the Cone has shifted back south again to the GA/SC border. Still some uncertainty IMO on where exactly the track lies, the stall and if there is a true WSW motion as the ECM and GFS indicate. If that happens just offshore upper SC Coast and then moves WSW then the ramifications are going to change wholeheartedly!

[meriland29]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

[terstorm1012]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

yes, the slowdown will cause upwelling of the shallow waters, causing some likely weakening. it will still likely be an intense hurricane at landfall late Thursday or early Friday morning.

[ronyan]

Note that the Cone has shifted back south again to the GA/SC border. Still some uncertainty IMO on where exactly the track lies, the stall and if there is a true WSW motion as the ECM and GFS indicate. If that happens just offshore upper SC Coast and then moves WSW then the ramifications are going to change wholeheartedly!

Yeah It would have to move pretty radically out of the cone to miss the US now sadly.

[Steve]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

Correct me if I’m wrong but the Gulf Stream is like 40-50 miles wide and maybe 100-120 miles off the SC/NC coast.

[artist]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

According to the NHC , she could but they still have her as a major upon approach to shore still.

[artist]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

Correct me if I’m wrong but the Gulf Stream is like 40-50 miles wide and maybe 100-120 miles off the SC/NC coast.

The coast of North Carolina is one of the best launching points for Gulf Stream access, located just 12-15 miles off the beaches of the Outer Banks, and the prospect of reeling in the big one attracts countless fishermen year after year.

But what is the Gulf Stream and why are its waters so significantly different from the cool breakers just off the beach? Why is it a harbor for countless species of fish and ocean life that would otherwise have no business being located off the coast of North Carolina?

The Gulf Stream is, essentially, a 40-50 mile wide current that runs through the Atlantic Ocean, but its breadth and speed can categorize it more accurately as a river. Like all other currents throughout the world, the Gulf Stream is formed by the sun, the wind, and the water.
http://www.ncbeaches.com/Features/Weather/GulfStream/

[supercane4867]

Water vapor imagery indicates that Florence has finally developed
the much anticipated dual outflow pattern, with outflow jets noted
in the northwestern and eastern quadrants. The latter outflow jet is
flowing into an upper-level low, which is acting as an impressive
mass sink near 25N/49W. These two outflow channels are producing
significant deformation stretching across Florence's inner-core,
which should aid in the re-strengthening process.

As noted in the 11AM discussion, Florence has developed a impressive dual outflow channel which is very visible on CIMSS analysis map

[sittingduck]

I found this part of the 11 am discussion interesting but confusing - especially the last line. I understand what they are saying about weakening, but are they saying that they don't believe that she will be as strong as the official intensity forecast?

here is the part By 48 h and
beyond, Florence's slow forward speed, coupled with the large eye
and relatively shallow depth of the warm water should induce some
upwelling beneath the cyclone that will initiate a slow weakening
trend. By 72 hours the vertical wind shear is expected to increase
to near 20 kt from the southwest, which will cause more significant
weakening to occur. However, given the large overall wind field of
Florence along with the large eye, only gradual weakening is
expected. Once Florence moves inland, the slow forward speed of 3-5
kt will result in rapid spin down and weakening of the wind field.
The new official intensity forecast is above of all of the intensity
guidance based on the aforementioned very favorable synoptic outflow
pattern, and to maintain continuity with the previous forecast.

[crimi481]

May be dumb question, but if Flo gets surrounded (to its north quads) would she be drawn more to the low pressure to its s. sw - in gulf?

[AnnularCane]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

yes, the slowdown will cause upwelling of the shallow waters, causing some likely weakening. it will still likely be an intense hurricane at landfall late Thursday or early Friday morning.

Wouldn't she have to stall over water for a while though? Or maybe I'm thinking of deeper waters.

[supercane4867]

CDO is becoming more smooth and symmetrical

[Michele B]

Is she likely the weaken from upwelling due to shallow waters the closer she gets to the United States?

yes, the slowdown will cause upwelling of the shallow waters, causing some likely weakening. it will still likely be an intense hurricane at landfall late Thursday or early Friday morning.

And more dangerous at that point might be tornadoes/water spouts that spring off it....that and the copious amounts of rain, of course.

[FLpanhandle91]

I do believe Florence will shed the cloud tops to her west and we should see a very symetrical CDO emerge as she transitions to an annular hurricane this evening.

Do you really think it's going to go annular? That's not something we see very often, even with Cat 5's. None of the models, including the hurricane models, are showing that kind of depiction. I'm not saying that it can't happen, but it doesn't seem likely unless you know something I don't. And if so, I'm all ears.

Just posted for discussion's sake. HWRF points to it for a brief period on its 06z run. Upper air envrionment appears conducive.

[psyclone]

Note that the Cone has shifted back south again to the GA/SC border. Still some uncertainty IMO on where exactly the track lies, the stall and if there is a true WSW motion as the ECM and GFS indicate. If that happens just offshore upper SC Coast and then moves WSW then the ramifications are going to change wholeheartedly!

The cone shifting has more to do with slower forward motion depicted after landfall on a slightly more west northwestward heading than anything. earlier projections took the center up close to the nc/va line inland after landfall. If you look at the actual projected landfall point...it's very near surf city on the latest advisory... which is close to equidistant between cape fear and cape lookout....and is a touch farther north than yesterday right now and a touch farther south than last night. I continue to find the consistency of the landfall hot zone rather impressive.