Major Hurricane Helene

[Tatamy]

6 minutes ago, bigtenfan said:

Question for those on the board more knowledgeable than I am.

I see that the TS warning is extended all the way down the Florida east coast yet the  TS Wind speed probabilities for MIA. FLL and WPB are only 7, 12 and 14% respectively. If the probabilities are that low why does the TS warning extend down that far?

 

Thanks in advance.

Due to the large size of the storm it is expected that squalls with winds to tropical storm force will move up the east coast of Florida.  This is the reason for the warning in my view.

[dan11295]

Also, significant inland flooding threat for southern apps in particular due to already saturated soils/pre-event and orographic lifting. 6z GFS showing 10-15" of rain over NE GA/W NC.

[kat5hurricane]

34 minutes ago, SnoSki14 said:

This could be more impactful than the strong Cat 4-5 hits as of late. It's all about the size when it comes to tropical systems and this one is huge. 

That's going to be quite the fetch on the West Coast of Florida. Even though Tampa and northward will likely miss the core, the surge impacts should be quite significant. The only saving grace is the speed of the system, it won't have an opportunity to pile up as much water as Katrina did for instance due to the faster movement but a major surge event nonetheless.

[WxWatcher007]

First light is beginning to reveal a much more organized TC near the Yucatán Channel, a harbinger of things to come. 

 

Recon, radar, and satellite all show a modestly organizing and gradually intensifying TC that will likely be a hurricane by the 11am full advisory. 

With shear reduced over the system itself and dry air most likely out of the way as an inner core forms in the next 12-18 hours, it looks like the runway is primed for Helene to take off in intensity late tonight into Thursday provided the center does not traverse the Yucatán.

You can tell dry air—something that has plagued systems across the basin all season—is not a factor at this time because of the expansive outflow and deep CDO convection that has persisted all night. I would watch the SE quadrant in case some of the drier air to the south wraps in. 

 

We have a system that’s already sub-980mb as a result, but that’s only part of the story.

Generally speaking, the wind field is still broad. A smaller system would be a hurricane by now with a tighter center. Helene is poised to become one of the largest named storms since 2000.

This will have tremendous implications for the forecast and scale of region wide impacts. 

First, the wind.

 

This is extraordinary to look at—tropical storm warnings from the Keys to coastal GA for a Gulf storm and hurricane warnings well into southern GA.

The storm already has TS winds expanding 175 miles out and that’ll grow substantially over the next day. In fact, you can already see how large Helene is using zoomed out satellite.

 

It’s going to take time for the RMW to tighten enough for major hurricane wind speeds to be found. What we’ll likely see are very low pressures with an expansive area of “modest” hurricane force FL then surface winds before RI takes place and tightens the inner core at that point. That said, I don’t believe the HAFS depictions of a small core and large TS field. This may limit peak wind potential some.

That’s not to say the potential for something on the order of a category four isn’t there because it is, but we’ll just have to see how the storm reacts to falling pressure.

Second, the surge. 

What may be lost in peak wind potential will likely be more than made up for in surge, which may be catastrophic in the Big Bend region and major in other locations. 

 

The difference in category will matter little given the surge potential. While a stronger or weaker peak wind could do significant damage inland, the coastal impacts are already baked in. 

Third, the rain.

If wind and surge weren’t enough—and both have the potential to be high end—rainfall looks to be a major concern well inland. A Predecessor Rain Event looks likely, and a HIGH risk for excessive rainfall has been issued. Extreme rainfall is possible and inland folks should not let their guard down just because Helene is currently well south. 

 

Fourth, severe potential.

Finally, we have severe potential on the east side of Helene. I think we need to see how banding sets up tomorrow and Friday, but a D2 enhanced risk is pretty significant for a TC.

 

This is a long post that didn’t even go into track (though I’m closely watching potential shifts west, possibly worsening wind impacts into the Panhandle and southern GA)

 

 

But for the general public the center will matter less than usual given the size of the wind field and surge potential all along the coast. 

[SnowenOutThere]

I think that the storms this season may be sorted into two categories. Beryl and now Helene seem to be on the rapidly intensifying categories which haven't (or likely won't) be plagued with dry air and shear and instead fully take advantage of the prime environment, with the other category consisting of storms unable to fully take advantage of the environment due to dry air and shear.   

[NorthHillsWx]

Tallahassee might get one of their worst storms 

[AStorms13]

Hi, long time lurker, first time poster.  Love weather, and super interested in tropical systems.  Am I correct in saying that the size of Helene has expanded quite a lot in the last 2 hours?

[CoastalWx]

Regarding the pressure, it's also possible the environmental air pressure is relatively low, which is why we have a 979mb TS. 

[40/70 Benchmark]

2 minutes ago, CoastalWx said:

Regarding the pressure, it's also possible the environmental air pressure is relatively low, which is why we have a 979mb TS. 

Yea, maybe that in conjunction with the size...both are factors in determining the wind-pressure relationship.

[StantonParkHoya]

We sure this is going to miss land?

[WishingForWarmWeather]

[CoastalWx]

1 minute ago, WishingForWarmWeather said:

 

Yeah was going to say, visible shows convection wrapping around, but IR kind of shows the illusion of the center closer to land and south. Microwave imagery helps here.

[WishingForWarmWeather]

Microwave link. Having the hardest time posting it as is, so here’s a link to it uploaded in Imgur.

[WishingForWarmWeather]

2 minutes ago, CoastalWx said:

 

Yeah was going to say, visible shows convection wrapping around, but IR kind of shows the illusion of the center closer to land and south. Microwave imagery helps here.

Core is kinda wild. Meat of it stretches nearly the entire Yucatán channel. 
 

really feels like when an eye does clear it will be massive. 

[nvck]

1 minute ago, WishingForWarmWeather said:

Microwave link. Having the hardest time posting it as is, so here’s a link to it uploaded in Imgur.

looks like the core of it should miss land, although it'll certainly be close

[schoeppeya]

Yeah recon shows how large the eye is with a huge area of lighter winds, pretty wild

[WishingForWarmWeather]

1 minute ago, nvck said:

looks like the core of it should miss land, although it'll certainly be close

Definitely cutting it close. Might help tighten it up a bit for some frictional convergence but I definitely don’t think we see a technical landfall. 

[CoastalWx]

That area from ATL to the N and NE are gonna get a shitload of rain. Big issues there I think especially foothills and mtns.

[WishingForWarmWeather]

Just now, CoastalWx said:

That area from ATL to the N and NE are gonna get a shitload of rain. Big issues there I think especially foothills and mtns.

Yeah - places like the Blue Ridge Mountains are in trouble. Nantahala River area, Ocala River area…Yeesh. Feels like a recipe for disaster with mudslides. 

[mclean02]

Oh side note concerning how a few models are showing another strong hurricane next week which would be wild.

[40/70 Benchmark]

It will take longer to tighen up, but another ramification of a core that large is that we may not even see an EWRC prior to landflall.

[nvck]

2 minutes ago, mclean02 said:

Oh side note concerning how a few models are showing another strong hurricane next week which would be wild.

Saw that, I won't talk too much about it on this thread, but yeah, another homebrew 'cane that the GFS (keep in mind at 240+ hrs) has landfalling on the FL panhandle around 950mb. Safe to say this likely won't verify, but worth keeping an eye on

[wxeyeNH]

27 minutes ago, AStorms13 said:

Hi, long time lurker, first time poster.  Love weather, and super interested in tropical systems.  Am I correct in saying that the size of Helene has expanded quite a lot in the last 2 hours?

Welcome AStorms.  The storm is becoming larger but what you see on the visible satellite is the higher cirrus canopy expanding.  That doesn't mean the surface winds are expanding necessarily.

[beanskip]

Tallahassee perspective: You may not know that Tallahassee and surrounding areas are some of the most tree-laden places in the country. A combination of live oaks, water oaks and countless pine trees create a canopy that can be breathtaking. Of course, those trees become weaponized by hurricanes and tornadoes.

For perspective, almost everyone in Tallahassee lost power during Hermine (a Cat 1 storm) and many lost power for more than a week.

It's hard to overstate the devastation that is coming to my area and the amount of repair work that will be required. That's to say nothing of the multiple rivers that empty into Apalachee Bay which will feel the effects of this unprecedented surge. Given that rivers are already running high from a rainy summer and prior storms, it's just an ugly recipe.

I'll try to share updates Thursday as long as I have power/cell service.

[Amped]

Already up to 36TJ IKE. Expecting a huge increase in the next 24 hrs with the increase in strength and size.

https://x.com/hwind/status/1838938345520435559

 

[cptcatz]

Interested to see where they mark the center from this last pass but from eyeballing the barbs, it looks like it's western movement has ended. Looks possibly a tad east of due north. 

[AccuChris]

It looks like perhaps a warming eye may be starting right on the far eastern edge of the Yucatan


.

[WxWatcher007]

The west trend has continued on the globals, with the 06z Euro and 06z GEFS ticking west. More in line with the spaghetti models.

[wxeyeNH]

8 minutes ago, beanskip said:

Tallahassee perspective: You may not know that Tallahassee and surrounding areas are some of the most tree-laden places in the country. A combination of live oaks, water oaks and countless pine trees create a canopy that can be breathtaking. Of course, those trees become weaponized by hurricanes and tornadoes.

For perspective, almost everyone in Tallahassee lost power during Hermine (a Cat 1 storm) and many lost power for more than a week.

It's hard to overstate the devastation that is coming to my area and the amount of repair work that will be required. That's to say nothing of the multiple rivers that empty into Apalachee Bay which will feel the effects of this unprecedented surge. Given that rivers are already running high from a rainy summer and prior storms, it's just an ugly recipe.

I'll try to share updates Thursday as long as I have power/cell service.

Didn't Michael  that wiped out Mexico Beach go over Tallahassee?  That was a Cat 5.  Just to the east of the eye is the worst and I don't remember if it went west of the city.  This will be scary because unlike Michael it will be dark.

[cptcatz]

And there it is. Is this the real turn to the northeast happening? Would be significantly earlier than models showed...