ATL: HELENE - Post-Tropical - Discussion

[Nimbus]

surface pressure drop at buoy 42056 down to 993.9 mb 20 minutes ago recon might find 980's and RI this mission?

[Steve]

What is the steering mechanism? We have a cold front moving in from the northwest here in Texas.

An alley between high pressure to the east and a cutting off low in a trough to the NW. the cut off low should mostly trap and entrain most of the energy and moisture after landfall we been talking about it for several days. And the situation has evolved. Run any of your favorite models at 500mb and it will show up very well. We are all learning new stuff with Helene.

[Zonacane]

993.9

free fall

It’s going to get worse soon.

[eastcoastFL]

We’ve got a pair of recon planes en route to Helene. Interested to see if the gradual improvement on visible has translated to any appreciable deepening.

We already have a buoy reporting a pressure of 995.3mb with a 17 knot wind, so it has absolutely deepened and the pressure is still dropping.

That same buoy is down to 993mb now.

[HurricaneBelle]

They seem pretty confident with predicting the panhandle/big bend area as landfall.(no warnings for tampa coast) I'm expecting where I'm on the west coast, north of Tampa to probably get winds equal to what we get after a cold front comes by, so i don't think I'll be doing much more than unless something changes tomorrow. Luckily i do live a little further inland from the beach.

A cold front?..there is a hurricane warning from Anclote River (Pinellas-Pasco Border) north which includes Pasco, Hernando and Citrus Counties and a tropical storm warning for Tampa Bay. There is a storm surge warning for Tampa Bay of 5-8 feet. There is a storm surge warning for the coast from Anclote River north of 6-10 feet.

Yeah the only time I remember getting TS-force winds behind a cold front was when Wilma passed to our south ahead of one in 2005, and those of course were enhanced by a very substantial pressure gradient. Otherwise winds with a strong cold front are usually no more than 25-35 MPH.

[MJGarrison]

Since we’re dealing with the 90th percentile in size, I would imagine that a drop in pressure would not necessarily correlate to the same windspeed increase as it would for a smaller storm.


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Depends on the size of the core.

A large overall storm would create a lower overall background pressure for any core, tight or otherwise.


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[ScottNAtlanta]

993.9

free fall

992.9 now

[NDG]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

[CrazyC83]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

That would support 991 mb, although it may be lower than that.

[Nimbus]

993.9

free fall

992.9 now

With winds from 330 so its moving NW on track

[Zonacane]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

That would support 991 mb, although it may be lower than that.

29.32 IN of Mercury, or 992.88 MB and it didn't get the center

[skillz305]

So if the trough over the eastern atlantic keeps pushing east and the "cut off bowling ball low" (thanks Levi) also keeps shifting further east, that allows a totally different steering lane towards Florida? In my non expert opinion, doesn't that mean what Helene is doing now, could be telling signs of the trough and low? How accurate are troughs and lows? Same accuracy as a Hurricane global model, etc? Sorry if it's a dumb question. After watching levi's video, I'm definitely wobble watching.

[ScottNAtlanta]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

Are we looking at the same buoy? I just refreshed it and it has 21.4 kts out of the North and 992.9 pressure buoy 42056

[eastcoastFL]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

That would support 991 mb, although it may be lower than that.

It's 992.8 now with 19kt winds out of the NNW

[NDG]

993.9

free fall

992.9 now

With winds from 330 so its moving NW on track

Glad you agree it did did not tracked south of the buoy as you initially thought it was going to do

[eastcoastFL]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

Are we looking at the same buoy? I just refreshed it and it has 21.4 kts out of the North and 992.9 pressure buoy 42056

Same one. Pressure still falling and winds increasing.

[CrazyC83]

Buoy's pressure now down to 993mb with 17 knot NNW winds, it passed over or just east of the buoy.

Are we looking at the same buoy? I just refreshed it and it has 21.4 kts out of the North and 992.9 pressure buoy 42056

Same one. Pressure still falling and winds increasing.

Recon could very well find something like 985 at this rate.

[Zonacane]

991.8

[weeniepatrol]

[grapealcoholic]

Huge Tower going up right on buoy (and near center)