ATL: EPSILON - Post-Tropical

[Iceresistance]

We have Major Hurricane Epsilon folks!

Proof?

18z best track updated to 100 kt and 955 mbar.

The NHC has not done anything yet.

[AxaltaRacing24]

Proof?

18z best track updated to 100 kt and 955 mbar.

The NHC has not done anything yet.

there is about a 0% chance this is not getting the upgrade.

[ClarCari]

Proof?

18z best track updated to 100 kt and 955 mbar.

The NHC has not done anything yet.

Barring any obvious weakening trends, the NHC hardly if ever releases advisories below BT strength.
It’s more common for them release them above BT strength based on any recon or satellite data they observe.
Even when they go below BT, it’s usually some time later like a full day in Sally’s case, or in TCR’s.

[Iceresistance]

18z best track updated to 100 kt and 955 mbar.

The NHC has not done anything yet.

there is about a 0% chance this is not getting the upgrade.

Either way, the next full advisory is at 4 PM CDT, I'll bet it's at 100 knots.

[ElectricStorm]

The NHC has not done anything yet.

there is about a 0% chance this is not getting the upgrade.

Either way, the next full advisory is at 4 PM CDT, I'll bet it's at 100 knots.

Almost certainly will be 100 kts

[EquusStorm]

Weakness in NW eyewall largely filled by new convention blowing up on SW side and wrapping rapidly around. The trend is steady state if not just a little strengthening so would be very shocked if they decided to run below BT in the advisory. Interested to see if it holds for the next recon plane to arrive.

[Hypercane_Kyle]

Proof?

18z best track updated to 100 kt and 955 mbar.

The NHC has not done anything yet.

Uh.. the ATCF is the NHC. Rather, it's the set of parameters the NHC feeds into the 18z models if I'm not mistaken. Sometimes the NHC changes the intensity between 18z and the advisory, but only when there's evidence supporting that change that comes in after the fact.

[EquusStorm]

CDO not as symmetrical as earlier, eye remains highly impressive but dry intrusions and cooler water might start to make their presence known before too long. As long as the eyewall doesn't open up it'll probably stay pretty impressive for a bit though

[Iceresistance]

Any moment now for the NHC

[Ryxn]

Any moment now for the NHC

Now.

[Dean_175]

Stadium effect!

Wow, that's a really good image of a stadium effect!

Can Epsilon really get to a Cat 4? I thought I read that the maximum possible was a Cat 3 with the 26 degree water temp. It looks like a total beast though so maybe that was wrong.

I suppose Theoretically a Cat. 5 is even possible in 26 degrees (not saying in this instance with Epsilon), it would just be sooo slow to occur that atmospheric instability would not be able to produce enough thunderstorms and convection to easily get it to that point before an EWRC takes place and chokes it or other things like dry air and shear stop it from ever getting close to that point. Really warm waters tend to produce convection alot faster, stronger, and more consistently as we saw in Delta and with Wilma.

If nothing disrupts Epsilon for the next several hours, it’s totally possible for it to reach Cat.4!

I agree that a borderline cat 4 may be possible, but I don't think a cat 5 is possible even in theory. MPIs calculations are supportive of a cat 3 or low end cat 4 in the region. I think 135-140mph would be the absolute highest ceiling for this systems intensity- but really I would guestimate it gets to 125-130mph at best.

The maximum hurricane intensity calculation is based on the idealized model of a hurricane as a Carnot heat engine (along with a few other meteorological assumptions). It basically assumes a perfect energy balance between latent heat generation (increases with SST and windspeed) and surface frictional drag (increases with wind speed). This isn't always a good model: storms sometimes derive energy from more than just the latent heat release. For example, when turning extratropical, the pressure may be lower than the maximum intensity equation predicts.

However for a "perfect" hurricane like a cat 5- a Carnot heat cycle is a fairly good model. The issue is not that it would take a long time to "gather" the energy over 26 degree water, but that over such water cat 5 winds would lead to more energy dissipation than the ocean can provide in the form of latent heat. Even if there were no EWRCs, the storm would plateau at a lower intensity than a 5. If a cat 5 goes over 26 degree water, it would gradually weaken.

[ClarCari]

Our OFFICIAL 4th major of the season.

[TallyTracker]

NHC went with 100 kts major hurricane!

[ScottNAtlanta]

This should add some ACE points

[kevin]

There we have it, major hurricane Epsilon. It's a rare name for a storm, but it seems to be associated with 2 of the most unique storms we've seen.

[EquusStorm]

Never any doubt. Now they just have to bump the intensity up significantly for last night and this morning in the best track and we're good.

[aspen]

Still a very impressive looking hurricane, especially for this latitude and time of year. It might be a little stronger when recon is there, and maybe it peaked between flights. It depends on what recon finds when it gets there in 1-2 hours.

[Hammy]

Took my eyes off the weather for a day and go from having a tropical storm to a major hurricane. October loves over-performing on intensity the last several seasons.

[supercane4867]

5PM discussion:

Epsilon has continued to defy expectations and rapidly intensify this afternoon.

Haven’t we heard this before? Epsilon doing its magic again

[EquusStorm]

October is my favorite month in pretty much all of the Northern Hemisphere. It's a total wild card that can either produce virtually nothing or rapidly intensifying majors, so each year is very different and never know what is in store. Also contains the most intense TC on record in every NHem basin (ATL, EPAC, WPAC, North Indian) except CPac.