ATL: FRANCINE - Remnants - Discussion

[Stormgodess]

 https://x.com/nadocast/status/1833527803708641461

Yeh the Tornadoes with Francine has been one of my biggest concerns because she has been expansive. With a lot of area for them to spin up.

With the big blob of convection in front of her sort of looking like it has "broken off" from the main rotation. Does that make the threat of Tornadoes less likely in that group of storms? Or does it not make a difference at all?

Sorry for the total newbie question

[GCANE]

 https://x.com/nadocast/status/1833527803708641461

Yeh the Tornadoes with Francine has been one of my biggest concerns because she has been expansive. With a lot of area for them to spin up.

With the big blob of convection in front of her sort of looking like it has "broken off" from the main rotation. Does that make the threat of Tornadoes less likely in that group of storms? Or does it not make no difference at all?

Sorry for the total newbie question

One of the main factors to spin up tornadoes is directional shear, that is, a change in wind direction at different heights in the atmosphere.
As Francine approaches landfall, low-level winds will be going east to west.
The trof will have winds going west to east higher up in the atmosphere.
This creates a large amount of spin in the atmosphere. In fact, it's about the worst-case scenario.
Most tropical systems create EF1 tornadoes when they are close to landfall or make landfall since they don't have the upper level wind flow to spin up stronger ones.
Looks like it may not be the case here. Could see some larger twisters this time around.
Sorry to have to be so blunt.

[tolakram]

Two videos



Link: https://youtube.com/watch?v=BcC4kj5l98s



Link: https://youtube.com/watch?v=odJL5BZpm6U

[tropicwatch]

Two videos

https://youtu.be/BcC4kj5l98s?si=PlghRF1VTrT_NSEk

https://youtu.be/odJL5BZpm6U?si=SstWUdBG0Rq7HLEN

I am new to the video stuff and wouldn't dare post one of mine. Tidbits and hurricanetrack are always good!

[underthwx]

If anyone addressed this already...my apologies....for the past couple of days...I have wondered how far east will Francines influence....require watches/warnings?....I think the NHC mentioned earlier...thar watches and warnings were added further eastward?....I wonder if these watches will eventually cover the Florida panhandle?......Francine has generated watches across a wide distance...from Northeastern Mexico...to east of Louisiana...but im not sure how far east....i do not recall another system...that has created such a wide swath of watches/warnings....

[EasyTiger]

Interesting dynamics as the convection to the northeast is starting to look like it's own entity

[GCANE]

10-15 knt increase in peak SFMR wind-speed measurements in the last hour

https://www.tropicaltidbits.com/recon/r ... series.png

[chaser1]

Interesting dynamics as the convection to the northeast is starting to look like it's own entity

On a quick visual observation, one might think that for sure. However, there actually are not any veering winds at any elevation level that depict any secondary vortex. It's amazing how many times a similar feature often exists with other developing (and even developed) T.S.'s & some hurricanes as well.

[chaser1]

10-15 knt increase in peak SFMR wind-speed measurements in the last hour

https://www.tropicaltidbits.com/recon/r ... series.png

Had to occur soon in keeping up with the pressure falls. Have to assume hurricane upgrade at 2:00pm

[Teban54]

10-15 knt increase in peak SFMR wind-speed measurements in the last hour

https://www.tropicaltidbits.com/recon/r ... series.png

Had to occur soon in keeping up with the pressure falls. Have to assume hurricane upgrade at 2:00pm

It doesn't look like recon has found any winds that justify a hurricane upgrade, however.

[Stormgodess]

 https://x.com/nadocast/status/1833527803708641461

Yeh the Tornadoes with Francine has been one of my biggest concerns because she has been expansive. With a lot of area for them to spin up.

With the big blob of convection in front of her sort of looking like it has "broken off" from the main rotation. Does that make the threat of Tornadoes less likely in that group of storms? Or does it not make no difference at all?

Sorry for the total newbie question

One of the main factors to spin up tornadoes is directional shear, that is, a change in wind direction at different heights in the atmosphere.
As Francine approaches landfall, low-level winds will be going east to west.
The trof will have winds going west to east higher up in the atmosphere.
This creates a large amount of spin in the atmosphere. In fact, it's about the worst-case scenario.
Most tropical systems create EF1 tornadoes when they are close to landfall or make landfall since they don't have the upper level wind flow to spin up stronger ones.
Looks like it may not be the case here. Could see some larger twisters this time around.
Sorry to have to be so blunt.

Thank you, I absolutely appreciate the honesty

[Ubuntwo]

10-15 knt increase in peak SFMR wind-speed measurements in the last hour

https://www.tropicaltidbits.com/recon/r ... series.png

Had to occur soon in keeping up with the pressure falls. Have to assume hurricane upgrade at 2:00pm

Peak SFMR and reduced FL average to 58kt. That lets them stay at 55 or bump to 60, up to forecaster discretion. In either case data does not support 65kt.

[ConvergenceZone]

I'm thinking somewhere around 85mph to 90 mph at landfall. The NHC discussions doesn't seem quite as bullish this morning as they did yesterday afternoon when they were expecting a strong 100mph at landfall.

[chaser1]

10-15 knt increase in peak SFMR wind-speed measurements in the last hour

https://www.tropicaltidbits.com/recon/r ... series.png

Had to occur soon in keeping up with the pressure falls. Have to assume hurricane upgrade at 2:00pm

Peak SFMR and reduced FL average to 58kt. That lets them stay at 55 or bump to 60, up to forecaster discretion. In either case data does not support 65kt.

Ah, okay then. I was under the impression that SFMR winds were now exceeding the previously established 55 knots per NHC

[ElectricStorm]

I'm thinking somewhere around 85mph to 90 mph at landfall. The NHC discussions doesn't seem quite as bullish this morning as they did yesterday afternoon when they were expecting a strong 100mph at landfall.

Shear and dry air should be increasing quite a bit before landfall which is why I think it will peak earlier and then weaken before landfall. Agree on 75-80kt landfall, but I think this gets to 85-90kts before

[GCANE]

Reed detailing the upcoming tornado outbreak

https://www.youtube.com/live/Q0kNdaCpAC ... W7WDChOe3I

[Nederlander]

Starting to look a little better for the LA folks... Francine is struggling to get going and running out of time. Not looking all that healthy/juiced right now either.

[MississippiWx]

Starting to look a little better for the LA folks... Francine is struggling to get going and running out of time. Not looking all that healthy/juiced right now either.

Not saying you won't be correct, but I've been anticipating these comments.

If you go back and look at the hurricane models, they don't really strengthen Francine until tonight into tomorrow morning. Again, not saying you aren't correct in the end, but the hurricane models have accurately predicted the structure. Most of them have the heavily east/southeast weighted convection rotating around to the northeast and completely around the center later tonight. If this doesn't happen tonight, then we can feel better. Still plenty of time for a ramp-up.

[TomballEd]

Just finished boarding the house up here in Central Lafourche and have the generators stashed behind the cars in the garage ready to go. I had a feeling yesterday they would be moving track east and here we are. Actually saw Archie, our parish president, shopping in Walmart (Raceland) this morning. Not sure if he needed supplies or was just getting down in the trenches with his residents.

Along Bayou Lafourche is another place I worry about, been down past the Golden Meadow speed-trap to Fourchon many times. Freshwater coming down the bayou and a couple of hundred yards away, the bay. I'd be nervous living there. When it looked a smidge W earlier I had concerns about Morgan City for similar reasons.

[jabman98]

Just went to the store in Houston. The water was cleaned out. I guess people have been paying attention. We're all a bit on edge after the derecho and Beryl. But now we'll be lucky to get even a drop of rain.