Major Hurricane Helene

[dseagull]

5 minutes ago, WxSynopsisDavid said:

Radar attenuation. Those towers are very large and blocking view of the west and south side of the storm. Reason why the intensification is surprising to you because you didn’t account for such.

 

3 minutes ago, WxWatcher007 said:

 

Things are about to pick up. 

Wouldn't be surprised if you lost cell signal with the outside of the wall.  Those towers keep backbuilding NE of their predecessors.  The lightning must be incredible from some vantages.   

The lack of radar returns on the SSW side are exactly 180 degrees counter to the tallest towers.   

Enjoy the ride, be safe. 

[MN Transplant]

Velocities from KTLH now 150-160mph aloft in the NE quadrant.

[schoeppeya]

6 minutes ago, WxSynopsisDavid said:

Radar attenuation. Those towers are very large and blocking view of the west and south side of the storm. Reason why the intensification is surprising to you because you didn’t account for such.

We literally do this every single storm storm. Because they always look this way. Regardless of if it’s attenuation or not, nobody should be surprised the backside eyewall looks ragged.

[DDweatherman]

Just now, MN Transplant said:

Velocities from KTLH now 150-160mph aloft in the NE quadrant.

Same with TBW even on the edge of the beam, it’s fierce no doubt. 

[CoastalWx]

6 minutes ago, WxSynopsisDavid said:

Radar attenuation. Those towers are very large and blocking view of the west and south side of the storm. Reason why the intensification is surprising to you because you didn’t account for such.

It is not radar attenuation. Both radars, TLH and TBW show it. Also noted on IR imagery. 
 

It’s clearly the intense convection helping. Other storms have shown some raggedness, but she’s really helping offset this with vigorous convection NW to NE of the center. It was just an observation. 

[NeffsvilleWx]

1 minute ago, WxSynopsisDavid said:

Radar attenuation. Those towers are very large and blocking view of the west and south side of the storm. Reason why the intensification is surprising to you because you didn’t account for such.

That’s not really attenuation.

What’s happening is that the density of the precipitable water is such that the majority of the transmit pulse energy is returned to the transmitter at that point. 

The energy that DOES get through that first “wall” is too weak to reflect a signal back through it, so it appears like there’s nothing beyond those first returns.

likely a hardware limitation if I had to guess. Though there might be a way with time domain reflectometry to recover some of that energy. Would be a cool grad student project.

[gallopinggertie]

Can someone shed some light on how such a quickly-moving storm is able to RI? I always heard that fast forward motion inhibits intensification. But obviously that’s not always true.

[OSUmetstud]

The northern eyewall is the only part producing lightning. The southern eyewall is likely not open but it's also weaker. 

[wthrmn654]

Buoy data says the eye has passed it

 The pictures that the buoy is sending back are pretty cool looking

 

[Doc Jon]

2 minutes ago, OSUmetstud said:

The northern eyewall is the only part producing lightning. The southern eyewall is likely not open but it's also weaker. 

Well, yeah.  That's just basic physics.  That's where you'd expect lightning to be.

[DDweatherman]

1 minute ago, OSUmetstud said:

The northern eyewall is the only part producing lightning. The southern eyewall is likely not open but it's also weaker. 

Agreed. People saying attenuation are denying the fact that we can see directly into the southern eyewall from TBW radar and the northern with TLH. It’s likely closed but it’s robbed of the convection which are those VHT’s and mesovorts in the N/NE. 

[Doc Jon]

speaking of core lightning...

 

wow!

[canderson]

Family that has a back yard along Sarasota Bay has the ocean lapping into their home tonight. First time in the 12 years of them there. 

[DDweatherman]

I’m interested to see if there are any frictional effects to tighten the convection and give this a bit more symmetry on its way in. NE eyewall is 58 miles from shore at the moment. 

[CoastalWx]

That’s a good looking storm on IR.

[gymengineer]

Latest radar panel- the eye is noticeably contracting.  

[wthrmn654]

What a nice eye. 

 

[schoeppeya]

Pretty incredible to see the similarities between this storm and Michael. The IR presentation and evolution approaching landfall is even remarkably similar 

[ldub23]

2 minutes ago, gymengineer said:

Latest radar panel- the eye is noticeably contracting.  

Land  interaction will tighten it  up a  bit

[NeonPeon]

8 minutes ago, NeffsvilleWx said:

That’s not really attenuation.

What’s happening is that the density of the precipitable water is such that the majority of the transmit pulse energy is returned to the transmitter at that point. 

The energy that DOES get through that first “wall” is too weak to reflect a signal back through it, so it appears like there’s nothing beyond those first returns.

likely a hardware limitation if I had to guess. Though there might be a way with time domain reflectometry to recover some of that energy. Would be a cool grad student project.

If this is so, why does a radar to the east of the storm in Tampa show the same as one in Tallahassee. The explanation makes no sense.

[dseagull]

If the lightning strikes continue, it'll be fun to use GIS comparison maps on overlay for Michael's approach.  

[csnavywx]

4 minutes ago, gymengineer said:

Latest radar panel- the eye is noticeably contracting.  

Gorgeous breakdown of barotropic instability resulting in scalloping on the eyewall.

[gymengineer]

This is quite the dropsonde from the eastern eyewall. 

[dan11295]

Definitely will not be weakening upon landfall. As has been stated by the NHC and others, Helene will have major inland wind impacts. Combination of strengthening large storm and rapid movement.

 

EDIT: That dropsonde might justify an upgrade to 120 kts.

[Nibor]

6 minutes ago, gymengineer said:

Latest radar panel- the eye is noticeably contracting.  

It's been contracting gradually all day.

[Master of Disaster]

29 minutes ago, BTRWx's Thanks Giving said:

Could it be going through an eyewall replacement cycle?

Not likely considering it has one last night. 

[MarkO]

Cedar Key area got to be experiencing some surge now. Wonder what it's going to look like in the morning. I hope everybody there evacuated. 

[dseagull]

1 minute ago, dan11295 said:

Definitely will not be weakening upon landfall. As has been stated by the NHC and others, Helene will have major inland wind impacts. Combination of strengthening large storm and rapid movement.

Power flashes already occurring a few miles south of Tallahassee.  This area hasn't had this type of storm in AGES... There will be unusually severe tree and infrastructure damage in areas that haven't recieved these conditions recently.  

[MN Transplant]

It is amazing how close this will end up being to Idalia’s landfall (Keaton Beach, south of Perry)

[DDweatherman]

3 minutes ago, Master of Disaster said:

Not likely considering it has one last night. 

I would call what happened last night a pseudo ERC. The eye started as nascent than made its way through the stages and in doing so there was the reorganization of the core & CDO. Not the true ERC’s we see with more developed, substantial canes.