ATL: FLORENCE - Post-Tropical - Discussion

[rickybobby]

Storm has an interesting XTRAP trend moving from southerly over the past 6 hours. This flies in the face of the NW turn and to me indicates that Ridge is building west, not retreating to the North, North East or staying stationary. An earlier EURO had this storm doing a loop over NC and back over SE Ga which to me showed some belief by that run the ridge would become stronger or move west with the storm but staying out in front. While the most recent EURO shows a straight line path after land fall, what I am seeing does not equal what the models are all telling me.

This movement generally west continues another day and I will skeddalle from NE Florida to points west starting with Tallahassee regardless of the cone!

So your saying Florida could still get hit?

[Emmett_Brown]

The 1 minute meso images show that as she nears 60W more of a N wobble or motion is occurring. Check it out here. Everything looks on track. The key with Florence landfalling either in SC or NC is going to be how quickly the ridging breaks down.
https://www.tropicaltidbits.com/sat/sat ... roduct=vis

The ridging never breaks down,that's why Florence moves wnw/nd into the SE US.

Correct. The overall ridge is massive, and covers most of the E US and the W Atlantic. It's the orientation of the bottom of the ridge that is supposed to guide her. Models show it tilted from SE to NW, which is why they have been predicting a NW acceleration. So the ridge doesn't break down... it just has a "shape" at the bottom that Flo will follow.

[plasticup]

Storm has an interesting XTRAP trend moving from southerly over the past 6 hours. This flies in the face of the NW turn and to me indicates that Ridge is building west, not retreating to the North, North East or staying stationary. An earlier EURO had this storm doing a loop over NC and back over SE Ga which to me showed some belief by that run the ridge would become stronger or move west with the storm but staying out in front. While the most recent EURO shows a straight line path after land fall, what I am seeing does not equal what the models are all telling me.

This movement generally west continues another day and I will skeddalle from NE Florida to points west starting with Tallahassee regardless of the cone!

So your saying Florida could still get hit?

The NHC thinks that is unlikely, so let's defer to their expertise here.

[Emmett_Brown]

There is some N component to the motion right now... but so little that you can only call the short term motion pretty much due W. I guess motions are averaged over 12 hour period, so it did gain a little latitude, but very little!

[Shell Mound]

"Florence well organized but why isn't the convection deeper such as say its counterpart near Africa? Environment.
Note the visible imagery how Florence's presentation is flat/smooth. Great organization but not great height into the atmosphere."

"They went to go find out some things. For steering, environment, et al.
One thing obvious is the environment is dry. It just is. Throughout the column. So a well organized Florence is strong & strengthening but so far it hasn't been explosive due to the abundance of drier air."

"Enviro aloft also preventing outflow from expanding. Too many features remain in the stream flow to allow expansion as yet. Until that changes slow & measured strengthening.
Also the ridge is being lifted by the Caribbean surge & the ridge is moving east. Keeps the N/E gate open."

"Based off GFS but just 48hrs out most models the same.
You get the breathing room finally and the storm can deepen. At same time those features shown evolve to allow the northern gate to be open to target more eastern NC barrier islands. Just can't dismiss this idea."

[cycloneye]

We will know a lot about how strong and where she is moving when the P-3 plane arrives shortly.Will be a very interesting mission and you can follow it in the recon thread

[Blinhart]

"Florence well organized but why isn't the convection deeper such as say its counterpart near Africa? Environment.
Note the visible imagery how Florence's presentation is flat/smooth. Great organization but not great height into the atmosphere."

"They went to go find out some things. For steering, environment, et al.
One thing obvious is the environment is dry. It just is. Throughout the column. So a well organized Florence is strong & strengthening but so far it hasn't been explosive due to the abundance of drier air."

"Enviro aloft also preventing outflow from expanding. Too many features remain in the stream flow to allow expansion as yet. Until that changes slow & measured strengthening.
Also the ridge is being lifted by the Caribbean surge & the ridge is moving east. Keeps the N/E gate open."

"Based off GFS but just 48hrs out most models the same.
You get the breathing room finally and the storm can deepen. At same time those features shown evolve to allow the northern gate to be open to target more eastern NC barrier islands. Just can't dismiss this idea."

Where did you find this, never saw this anywhere?

[Shell Mound]

"Florence well organized but why isn't the convection deeper such as say its counterpart near Africa? Environment.
Note the visible imagery how Florence's presentation is flat/smooth. Great organization but not great height into the atmosphere."

"They went to go find out some things. For steering, environment, et al.
One thing obvious is the environment is dry. It just is. Throughout the column. So a well organized Florence is strong & strengthening but so far it hasn't been explosive due to the abundance of drier air."

"Enviro aloft also preventing outflow from expanding. Too many features remain in the stream flow to allow expansion as yet. Until that changes slow & measured strengthening.
Also the ridge is being lifted by the Caribbean surge & the ridge is moving east. Keeps the N/E gate open."

"Based off GFS but just 48hrs out most models the same.
You get the breathing room finally and the storm can deepen. At same time those features shown evolve to allow the northern gate to be open to target more eastern NC barrier islands. Just can't dismiss this idea."

Where did you find this, never saw this anywhere?

They're linked tweets. Simply click on the quotes. I wanted to save bandwidth for readers here.

[SconnieCane]

Some peeps still nervous about Flordia, but if there was going to be an outlier track I'd give the edge to a northerly one into Chesapeake Bay or Jersey. There's not really a door open for OTS. NC/SC border to the OBX still strongly favored, though.

[p1nheadlarry]

The sharp increase in southwesterly vertical wind shear shortly before landfall is related to the amplification and retrogression of the mid-level trough over the central subtropical North Atlantic. As this trough does so, it erodes and displaces the anticyclone over Florence, resulting in shear. The slowing movement of Florence as it nears the coastline will only enhance the strength of the storm-relative shear, and also result in upwelling of relatively cooler shelf waters as the storm leaves the Gulf Stream. Additionally, the shear vectors will certainly draw in some drier continental air; however, the absence of an approaching large-scale trough from the west mitigates this somewhat. Nevertheless, even if Florence were to strengthen to near-Cat-5 status over the thirty-six hours, the increase in shear and upwelling, owing to both the trough and the reduction in forward speed, will cause significant weakening in the intensity of Florence before landfall. The rate of weakening could well be faster than the initial intensification. I think a Cat-4 landfall is very unlikely, despite the NHC's forecast. Florence, while quite likely to reach Cat-4 status over the Gulf Stream, will probably be a Cat-2 or low-end Cat-3 at landfall. I would go with a peak of 130-135 knots over the Gulf Stream and a landfall intensity of 90-105 knots over eastern NC. This is more in line with climatology for major hurricanes at the latitude of eastern NC.

Florence has already proven you can not go with Climatology with her. There will not be much to cause her to weaken, there is nearly no wind shear forecasted for her in the future. She should be able to get well in the Cat 5 status, Landfall should be at the lowest Cat 4.

I saw it posted earlier, but SHIPS does forecast wind shear increasing as it nears the coast. The two other Cat-4 storms of note, Hugo and Hazel, were fast movers and didn't weaken too much. I think Florence will be a low-end 3 as well, still bad.

[supercane4867]

While Florence is still intensifying, I expect her to go through at least one EWRC before reaching the ultimate peak strength. The eye and wind field size at landfall will be much larger than they are right now.

[p1nheadlarry]

Stronger ridging obviously in place. The afternoon Euro run will tell a lot. My brothers wife is pregnant with 2 kids home alone in Wilmington. Told her to leave tonight to stay with family as tomorrow the coastal zoo begins. Parents in Wilmington are staying put which is a good idea if not in a flood zone. Evacuation is going to be far over done and I expect parking lot conditions by Tues afternoon.

They reverse the eastbound lane on I-40 during evacuations at least

[supercane4867]

The sharp increase in southwesterly vertical wind shear shortly before landfall is related to the amplification and retrogression of the mid-level trough over the central subtropical North Atlantic. As this trough does so, it erodes and displaces the anticyclone over Florence, resulting in shear. The slowing movement of Florence as it nears the coastline will only enhance the strength of the storm-relative shear, and also result in upwelling of relatively cooler shelf waters as the storm leaves the Gulf Stream. Additionally, the shear vectors will certainly draw in some drier continental air; however, the absence of an approaching large-scale trough from the west mitigates this somewhat. Nevertheless, even if Florence were to strengthen to near-Cat-5 status over the thirty-six hours, the increase in shear and upwelling, owing to both the trough and the reduction in forward speed, will cause significant weakening in the intensity of Florence before landfall. The rate of weakening could well be faster than the initial intensification. I think a Cat-4 landfall is very unlikely, despite the NHC's forecast. Florence, while quite likely to reach Cat-4 status over the Gulf Stream, will probably be a Cat-2 or low-end Cat-3 at landfall. I would go with a peak of 130-135 knots over the Gulf Stream and a landfall intensity of 90-105 knots over eastern NC. This is more in line with climatology for major hurricanes at the latitude of eastern NC.

Florence has already proven you can not go with Climatology with her. There will not be much to cause her to weaken, there is nearly no wind shear forecasted for her in the future. She should be able to get well in the Cat 5 status, Landfall should be at the lowest Cat 4.

I saw it posted earlier, but SHIPS does forecast wind shear increasing as it nears the coast. The two other Cat-4 storms of note, Hugo and Hazel, were fast movers and didn't weaken too much. I think Florence will be a low-end 3 as well, still bad.

It depends on when will Florence starts to slow down. According to the euro any slowing won't occur until after landfall.

[Mouton]

Storm has an interesting XTRAP trend moving from southerly over the past 6 hours. This flies in the face of the NW turn and to me indicates that Ridge is building west, not retreating to the North, North East or staying stationary. An earlier EURO had this storm doing a loop over NC and back over SE Ga which to me showed some belief by that run the ridge would become stronger or move west with the storm but staying out in front. While the most recent EURO shows a straight line path after land fall, what I am seeing does not equal what the models are all telling me.

This movement generally west continues another day and I will skeddalle from NE Florida to points west starting with Tallahassee regardless of the cone!

So your saying Florida could still get hit?

I am saying it is more of a possibility than the zero that is being portrayed. My key point is if it keeps moving west defying all modelreasoning, the possibility grows. My opinion is based on fact there are no steering currents, like troughs, together with an unusual deep blocking high to the north and east with one supposed to be building in from the west. Kind of like Tennyson's positioning facing the Light Brigade. IMO, the models do not a lot of experience with forecasting from these conditions.

Of course the most important thing is to remember I am not an expert so for any life and property decisions I would defer to the NHC and other official experts who are paid for making these projections.
I am speculating upon what my eyes see, I don't have anywhere the amount of data points they do.

[ronjon]

if this motion continues for the next 2 hours. we will likely see out first short term track adjustment to the west.. probably 1st of many..

i am with you until we go down, i have been thinking further west since saturday..gfs is so biased towards the right its sad, lets see..today is the day of truth

I have to say you guys are persistent if nothing else. You'll score a major win if correct. Aric, do you still see significant southward shifts to the storm landfall? I'm thinking perhaps as far as central SC but unlikely any further south than that based on the European ensemble output.

[Ntxw]

The sharp increase in southwesterly vertical wind shear shortly before landfall is related to the amplification and retrogression of the mid-level trough over the central subtropical North Atlantic. As this trough does so, it erodes and displaces the anticyclone over Florence, resulting in shear. The slowing movement of Florence as it nears the coastline will only enhance the strength of the storm-relative shear, and also result in upwelling of relatively cooler shelf waters as the storm leaves the Gulf Stream. Additionally, the shear vectors will certainly draw in some drier continental air; however, the absence of an approaching large-scale trough from the west mitigates this somewhat. Nevertheless, even if Florence were to strengthen to near-Cat-5 status over the thirty-six hours, the increase in shear and upwelling, owing to both the trough and the reduction in forward speed, will cause significant weakening in the intensity of Florence before landfall. The rate of weakening could well be faster than the initial intensification. I think a Cat-4 landfall is very unlikely, despite the NHC's forecast. Florence, while quite likely to reach Cat-4 status over the Gulf Stream, will probably be a Cat-2 or low-end Cat-3 at landfall. I would go with a peak of 130-135 knots over the Gulf Stream and a landfall intensity of 90-105 knots over eastern NC. This is more in line with climatology for major hurricanes at the latitude of eastern NC.

Florence has already proven you can not go with Climatology with her. There will not be much to cause her to weaken, there is nearly no wind shear forecasted for her in the future. She should be able to get well in the Cat 5 status, Landfall should be at the lowest Cat 4.

I saw it posted earlier, but SHIPS does forecast wind shear increasing as it nears the coast. The two other Cat-4 storms of note, Hugo and Hazel, were fast movers and didn't weaken too much. I think Florence will be a low-end 3 as well, still bad.

It doesn't have the deep cold tops involved for a Cat 5 yet. It may not given the latitude but cat 4 should be easy.

[sponger]

Stronger ridging obviously in place. The afternoon Euro run will tell a lot. My brothers wife is pregnant with 2 kids home alone in Wilmington. Told her to leave tonight to stay with family as tomorrow the coastal zoo begins. Parents in Wilmington are staying put which is a good idea if not in a flood zone. Evacuation is going to be far over done and I expect parking lot conditions by Tues afternoon.

They reverse the eastbound lane on I-40 during evacuations at least

Quite true. NC and SC are pros at this while Florida pretends that its impossible and does not help. However, I would not expect any Contra flow help until Wed at the earliest.

[Hurricane Andrew]

Classic look of deep convection rolling around the eyewall...once that solidifies at a -60º to -80º ring, we could be looking at RI up to a strong 4, maybe a weak 5.

Dry air would have to try real hard to penetrate this thing...SHIPS has shear very low until about D3. Through 60 hours, the highest it gets is 10kts. 18kts at HR 72, increasing to a 25kt maximum at HR108. Now, that's nothing compared to what she was dealing with a few days ago (30-40kts in a much less conducive environment). So 12-18 hours of 15-20kt shear before landfall...might take off a tiny bit. Probably not that much.

SHIPS notes how much shear goes into intensity forecast...and it never has a negative effect for the 12z SHIPS.

12z SHIPS is also the most intensive SHIPS run I've seen so far, maxing out at 127kts (131 for LGEM) at HR+60, decreasing to 115kts (that's a cat 4) at landfall. SSTs are 29ºC or higher until landfall. OHC around 30 or higher (lowest of 27).

I don't see any reason this won't be a major hurricane at landfall. Last-minute preparations should be conducted now. We are 3.5 days out. It's go time if you are in the path of this thing.

[Blinhart]

"Florence well organized but why isn't the convection deeper such as say its counterpart near Africa? Environment.
Note the visible imagery how Florence's presentation is flat/smooth. Great organization but not great height into the atmosphere."

"They went to go find out some things. For steering, environment, et al.
One thing obvious is the environment is dry. It just is. Throughout the column. So a well organized Florence is strong & strengthening but so far it hasn't been explosive due to the abundance of drier air."

"Enviro aloft also preventing outflow from expanding. Too many features remain in the stream flow to allow expansion as yet. Until that changes slow & measured strengthening.
Also the ridge is being lifted by the Caribbean surge & the ridge is moving east. Keeps the N/E gate open."

"Based off GFS but just 48hrs out most models the same.
You get the breathing room finally and the storm can deepen. At same time those features shown evolve to allow the northern gate to be open to target more eastern NC barrier islands. Just can't dismiss this idea."

Where did you find this, never saw this anywhere?

They're linked tweets. Simply click on the quotes. I wanted to save bandwidth for readers here.

So what is his credentials, is his like mine, going with what he has learned in life.

[GCANE]

Kermit in the air