ATL: HELENE - Post-Tropical - Discussion

[toad strangler]

Now moving NNE.

https://i.imgur.com/sKDcvUj.png

uhh, that's a wee bit early for a E component.

[MJGarrison]

Now moving NNE.

Earlier than the models anticipated. Not good.

She’s a monster.

Possibly just a wobble?


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[USTropics]

Helene is one of the more impressive tropical storm you will see. Classic satellite presentation. Very little shear if any impacting the cyclone. Once Helene moves clear of the Yucatan it should ramp up quickly. Could peak out as a Cat-4. Lets hope it falls apart before landfall......MGC

not according to the shear map, granted it doesn't look nearly as sheared as this map indicates it should be. It's also supposed to enter an area of high shear just to the north, what's going to cause that shear to drop today?
https://tropic.ssec.wisc.edu/real-time/atlantic/winds/wg8shrZ.GIF

A few things to keep in mind. This is a static shear map (not a forecast). Also, this product doesn't do a great job of analyzing directional shear. If the storm motion is in the same direction as the shear vector. The HWRF analyzes this with 3kt of directional shear:


Sparta/Alex also has TDR (tail dopper radar data from the recon flights) and that also provides a better picture of the structure:


 https://twitter.com/cyclonicwx/status/1838915815111852341

[3090]

That was a pretty significant pulse up phase, Helene is well on its way towards establishing an inner core now. From radar and recon data it does look like there might be some faint mid-level dry air entrainment that it's still working through. Latest recon pass is holding pressure steady at about 979mb:
https://i.imgur.com/d16BF18.png

That dry air over the YP that Levi discussed in his video yesterday definitely got partially ingested, and that is probably the only factor has inhibited development so far since the shear went down. Still looking like a beast though.

that dry air is gone. really nothing to hold her back after she clears the tip in the next few hours. friends in Tally are bugging out to Pensacola.

That is FALSE!! The dry air is still feeding into Helene. See the pros statements. And appropriate satellite imagery.

[Jag95]

Now moving NNE.

https://i.imgur.com/sKDcvUj.png

uhh, that's a wee bit early for a E component.

Or a refix on an elliptical center. Radar still looks NNW to me.

[Nimbus]

Now moving NNE.

https://i.imgur.com/sKDcvUj.png

That’s sooner than forecasted, right? Not by much, but I feel like they had a turn to the east starting later in the day.

Its only .1 degrees east for every 1 degree north so that would still be west of the Tampa buoy.

[GCANE]

Looking a successive eye drops, the core was moderately dry but is moistening up.

[kevin]

Another recon pass by NOAA3 and this might be the one that does it. 978.7 mbar with 7 kt FL winds -> 978 mbar. But more importantly, 78 kt FL winds, which is more than sufficient for an upgrade to 65 kt at the next advisory.

[cycloneye]

Hurricane at 11 AM with those winds over 65kt and a peak of 78kt.

[ColdMiser123]

Another recon pass by NOAA3 and this might be the one that does it. 978.7 mbar with 7 kt FL winds -> 978 mbar. But more importantly, 78 kt FL winds, which is more than sufficient for an upgrade to 65 kt at the next advisory.

This supports 70 kt at the surface - definitely more than enough for a hurricane upgrade at 11 am.

[jasons2k]

Looks like they’ve found a hurricane.

[Kazmit]

Another recon pass by NOAA3 and this might be the one that does it. 978.7 mbar with 7 kt FL winds -> 978 mbar. But more importantly, 78 kt FL winds, which is more than sufficient for an upgrade to 65 kt at the next advisory.

That might be good enough to go straight to 70kts. The NHC usually doesn't do that though.

[USTropics]

Now moving NNE.

https://i.imgur.com/sKDcvUj.png

uhh, that's a wee bit early for a E component.

Or a refix on an elliptical center. Radar still looks NNW to me.

This. Don't fix too much on a single recon point, especially as Helene is still building an inner core (expect some oscillating/contracting type movements as the system becomes vertically stacked). A blend of multiple points will provide a better assessment of true storm motion.

[jdjaguar]

That dry air over the YP that Levi discussed in his video yesterday definitely got partially ingested, and that is probably the only factor has inhibited development so far since the shear went down. Still looking like a beast though.

that dry air is gone. really nothing to hold her back after she clears the tip in the next few hours. friends in Tally are bugging out to Pensacola.

That is FALSE!! The dry air is still feeding into Helene. See the pros statements. And appropriate satellite imagery.

meant to say almost gone...look at the water vapor loop. chill out

[Zonacane]

Now moving NNE.

https://i.imgur.com/sKDcvUj.png

uhh, that's a wee bit early for a E component.

Probably getting tugged by intense towers and convection on the Eastern and Northern side of the storm.

[GCANE]

SPC is forecasting a significant tornado threat for tomorrow night along the SE GA shore

https://www.spc.noaa.gov/products/outlook/day2otlk.html

[wxman57]

I was running SLOSH this morning. A large Cat 3 moving into Apalachee Bay from the south or SSW would produce a 30 ft surge, not 10-15. Forward speed 25 mph at landfall.

[Beef Stew]

Should be getting a hurricane designation at 10:00 CDT. Expecting 65 kts, but there's certainly a case to be made for 70.

[Jr0d]

Should be getting a hurricane designation at 10:00 CDT. Expecting 65 kts, but there's certainly a case to be made for 70.

The NOAA plane found 78kt flight winds so 70 kts is reasonable.

[Zonacane]

I was running SLOSH this morning. A large Cat 3 moving into Apalachee Bay from the south or SSW would produce a 30 ft surge, not 10-15. Forward speed 25 mph at landfall.

Jesus, Katrina’s record might get beaten.