Major Hurricane Helene

[hlcater]

Recon just got the first fix of the evening. 990.5 extrap

 

[Roger Smith]

Storm is near wtere Wilma set a record for rapid intensification in Oct 2005. Paths diverged afterwards (not expecting as fast RI this one, RI will be late Wednesday 26N or so)

[hawkeye_wx]

Center dropsonde says 991 mb.

[gopack42]

Definitely a noob question here, but can sea bouys measure rainfall rates, etc?  I didn't know if bouys closer to shore could tell how much precip is falling to give an idea of what might be expected ahead of time.  I do realize that location matters in a storm and things rapidly change, but it'd be interesting to see how much rain falls out at sea.  Thanks everyone 

[hawkeye_wx]

It appears the second recon plane, which took off from Biloxi a couple hours ago, encountered a problem while flying through the Yucatan Channel, so they had to end the flight and turn back.

[SnowGoose69]

18Z Euro somewhat east of the 12Z run

[WxWatcher007]

The 18z hurricane models (HWRF, HMON, HAFS-A&B) show just how critical the next few 12-18 hours may be with the track of the LLC near the Yucatan. Each run misses the landmass and all develop a formidable major hurricane as a result. 

[cardinalland]

This storm's got that look that John in the EPAC just had while it was developing. I'm expecting Hurricane Helene by 11am tomorrow. I also imagine that surge could be a bigger deal for this one than for some others recently, because it has a little more time over water, its larger size/lower pressure, and the interaction that it will have with the trough over the deep south.

[Radtechwxman]

That CDO really getting healthy now over center. It's getting more symmetrical, getting colder, and starting to fan out signifying less shear and better upper outflow. We will likely have a hurricane tonight. Big question is does it go over Yucatan and get disrupted. 

[wxeyeNH]

Am I reading the recon right?  Down to 986mb?

 

[GaWx]

4 hours ago, beanskip said:

I would actually love a primer on these spagheti plots -- I rarely see much correlation between them and actual individual model runs. What are they? 

The spaghetti plots are of the most recent run of these models. AVN is GFS, UK is UKMET, etc

[Boston Bulldog]

Man this thing is a behemoth, look at that gigantic outer band draped over Jamaica.
 

These CAG storms can bring quite the vorticity payload as they head north. Major rossby wave perturbations likely downstream as Helene rots in the mid-latitudes.

I haven’t looked, but this would likely be a “reshuffle the deck” situation for the extratropical circulation across the N-ATL and Europe

[hlcater]

7 minutes ago, wxeyeNH said:

Am I reading the recon right?  Down to 986mb?

 

Definitely legit too. Look at the temp spike/Td drop associated with it

[csnavywx]

1 hour ago, dbullsfan said:

Question that I've wondered for a while but never asked (and not trying to get too sidetracked but this storm seems like a great example to bring it up with). 

 

Why is it with some of these storms, and with Helene being such a big storm are there huge breakups in the rain bands. As a novice onlooker I see the projected radar paths shown by local Mets and the national shows and for example where I am at about 25 miles inland near Tampa it looks like while we get some outer bands and some more as the center comes a little closer due west but a lot of breaks in between the bands so we really don't get much at all on the rain side.  whereas with other storms it seems much lusher (I can't think of a better word at the moment) and the rain is more consistent throughout the storm passing. Is this something with the off-shore radar or are there just big gaps in where the rain is outside of the core? 

 

Sorry for the newb question but always been curious and figured we aren't into storm mode just yet with this one. Thanks for the feedback 

Sometimes has more to do with the in-situ environment around the storm. If it's in a large, moist envelope with extra forcing mechanisms to help (like the entrance region on a jet or a nearby stalled front), then it's reasonable to expect more/more intense rain bands. Low wind shear environments also favor more/more intense rain bands as less dry air can be advected in to disrupt the vertical advection of moisture via areal convection.

[beanskip]

33 minutes ago, SnowGoose69 said:

18Z Euro somewhat east of the 12Z run

Can you please define "somewhat?" 

[hawkeye_wx]

The newest recon pass actually found the center jogged a bit southwest since the last fix, so the surface center is not under that blob of convection, but just off the south edge.

The dropsonde says 990 mb with 17 kt wind.

[GaWx]

7 minutes ago, beanskip said:

Can you please define "somewhat?" 

~40 miles E. Nothing unusual this far out.

[user13]

7 minutes ago, hawkeye_wx said:

The newest recon pass actually found the center jogged a bit southwest since the last fix, so the surface center is not under that blob of convection, but just off the south edge.

The dropsonde says 990 mb with 17 kt wind.

986

[Radtechwxman]

6 minutes ago, hawkeye_wx said:

The newest recon pass actually found the center jogged a bit southwest since the last fix, so the surface center is not under that blob of convection, but just off the south edge.

The dropsonde says 990 mb with 17 kt wind.

Interesting. Wonder if that's cuz of shear or just part of the LLC and MLC trying to organize and align with each other. 

[user13]

16 minutes ago, Boston Bulldog said:

Man this thing is a behemoth, look at that gigantic outer band draped over Jamaica.
 

These CAG storms can bring quite the vorticity payload as they head north. Major rossby wave perturbations likely downstream as Helene rots in the mid-latitudes.

I haven’t looked, but this would likely be a “reshuffle the deck” situation for the extratropical circulation across the N-ATL and Europe

Let's if it could escape the Yucatan and have a core in tack then it could really take off

[MANDA]

Getting “the look”.  Expect hurricane status by 11:00 am advisory tomorrow.

Center should graze Yucatán but I wouldn’t expect landfall so it should have minimal effect on circulation / intensity.  

Surge on west Coast of FL could be bad especially Tampa vicinity on northward.  Water will pile toward the coast and motion of Helene and associated wind trajectory will prevent it from flowing back out until center is well inland.  

I’d also watch for potential nudges east in TPC track over next several advisories.  Maybe by as much as 50+ miles.

[Radtechwxman]

3 minutes ago, MANDA said:

Getting “the look”.  Expect hurricane status by 11:00 am advisory tomorrow.

Center should graze Yucatán but I wouldn’t expect landfall so it should have minimal effect on circulation / intensity.  

Surge on west Coast of FL could be bad especially Tampa vicinity on northward.  Water will pile toward the coast and motion of Helene and associated wind trajectory will prevent it from flowing back out until center is well inland.  

I’d also watch for potential nudges east in TPC track over next several advisories.  Maybe by as much as 50+ miles.

For RI though need that center right under the convective blob and if it's more on the edge strengthening may be more gradual till then. But we are entering the diurnally favorable time for strengthening. 

[StantonParkHoya]

15 minutes ago, MANDA said:

Getting “the look”.  Expect hurricane status by 11:00 am advisory tomorrow.

Center should graze Yucatán but I wouldn’t expect landfall so it should have minimal effect on circulation / intensity.  

Surge on west Coast of FL could be bad especially Tampa vicinity on northward.  Water will pile toward the coast and motion of Helene and associated wind trajectory will prevent it from flowing back out until center is well inland.  

I’d also watch for potential nudges east in TPC track over next several advisories.  Maybe by as much as 50+ miles.

You should provide a basis for claims on why you think the track will be east

Unsubstantiated claims or hypotheses without rationale amount to wishcasting

[40/70 Benchmark]

3 minutes ago, StantonParkHoya said:

You should provide a basis for claims on why you think the track will be east

Unsubstantiated claims or hypotheses without rationale amount to wishcasting

I think powerful hurricanes recurving a bit faster than modeled when interacring with a trough is pretty tacit, rudimentary meteorolgy.

[40/70 Benchmark]

1 minute ago, wthrmn654 said:

Is that some dry air on the west side? 

 

I think its atill trying to mix out the deleterious influence of the ULL as the core becomes established. 

[Amped]

Cuba radar isn't showing any sort of an eyewall yet. Probably means there's still multiple and or misaligned centers. High tchp and consolidation are allowing it to deepen anyway.

[MattPetrulli]

986 pass earlier probably just from a mesovort. Pressure came up a bit, but this is probably the beginning of core construction given the temperature spike present. 

[StantonParkHoya]

[SnowGoose69]

22 minutes ago, 40/70 Benchmark said:

I think powerful hurricanes recurving a bit faster than modeled when interacring with a trough is pretty tacit, rudimentary meteorolgy.

In this case I feel the closer it is to strong 3 or more upon nearing landfall it’s likely go NNE or NE longer after landfall because the upper low won’t capture it til it’s undergoing major weakening.  So no question the NNW hook is probably delayed more if this comes in as a 4 vs a 2.  As for whether the track prior to landfall is impacted by the strength I’m not sure.  It’s possible if that upper low has tugging power reaching more into the Gulf at 48 hours then maybe a weaker cane will be going more 010 vs 040 at landfall    

[jbenedet]

11 minutes ago, StantonParkHoya said:

Talahassee, Atlanta.