ATL: DELTA - Post-Tropical - Discussion

[Ryxn]

Pinhole eye clearing out now....z

If Wilma could hit 185 mph and 882 mbar I see no reason Delta couldn't peak at 160 mph / 920 mbar given it's in a moist environment with virtually no shear and it appears to be absorbing ex-Gamma as well which will slow the storm.

[aspen]

Delta keeps pumping out deeper and deeper convection. This might make a run for a T#8.0 pinhole like Gilbert.

[ElectricStorm]

Delta keeps pumping out deeper and deeper convection. This might make a run for a T#8.0 pinhole like Gilbert.

Well that is certainly not the post I wanted to see right when I woke up... Geez Delta is really going ham out there

[Hypercane_Kyle]

Dropsonde was 959mb but with a 71 mph wind, so probably closer to 955-956mb?

[aspen]

OHC is actually slightly higher closer to the Yucatán. Absolutely bonkers rocket fuel for the next 18-24 hours.

[kevin]

Dropsonde was 959mb but with a 71 mph wind, so probably closer to 955-956mb?

If this is still a cat 2 it's the lowest pressure recorded for one since Alex in 2010.

[USTropics]

Now that we're talking about ACE, does anyone have a link to a place where we can find the ACE of all or at least many storms? It will be interesting to compare Delta to other Caribbean cruisers like Wilma later on.

I've been working on this project. I have all the ibtracs uploaded to Google Sheets, and have created the ACE formula and a pivot table to look at each season/system. I haven't 100% confirmed every system is accurate (there was quite a bit of filtering work that went in to it), so let me know if anyone sees any errors.

https://docs.google.com/spreadsheets/d/ ... sp=sharing

[hipshot]

Now that we're talking about ACE, does anyone have a link to a place where we can find the ACE of all or at least many storms? It will be interesting to compare Delta to other Caribbean cruisers like Wilma later on.

I second your request but sadly I don't have the information. I tried a google search but it didn't turn up much. This info is surprisingly difficult to find IMO.

http://tropical.atmos.colostate.edu/Realtime/

Edit: Nevermind, I can't find the ACE for individual storms pre-2020 on that site....sorry

Click on the basin (North Atlantic) and it will have a chart with each storm on it.

[supercane4867]

Reed is going to Cancun. No words from Josh yet.

 https://twitter.com/reedtimmeraccu/status/1313440231601782785

[GCANE]

Eye relative humidity measured at 86%.
Up from 63% last night.
Watching the trend today if it continues to increase as a possible precursor to a EWRC.

Why is RH increase a sign of EWRC? Decreased radial inflow leading to less latent heating in the eye and thus +PV tendency in the eye?

Got it out of this reference.
https://www.ssec.wisc.edu/~kossin/artic ... l_2012.pdf

[NotoSans]

Dropsonde was 959mb but with a 71 mph wind, so probably closer to 955-956mb?

The rule of thumb is to deduct 1mb per 10kt winds, so it actually yields 953mb if the data are valid.

[Hypercane_Kyle]

No evidence of double-wind maximum yet.

[SconnieCane]

There's something interesting about Delta's current satellite presentation...

It does not have the "classic" look of a mature major hurricane. The outflow channels aren't quite there. It has a big secondary blob of convection to the south where one of them should be (rather like that "twin" Matthew had). However, it has one of the meanest looking CDOs I've seen in the Atlantic basin in a long time; if ever (more impressive than Dorian, about on par with Irma during its initial run to Cat. 5 but smaller) It is taking on a very compact "buzzsaw" look rather like Andrew on approach to Florida.

[us89]

Recon confirms a high-end category 2 hurricane, but the latest Dvorak estimate from ADT is still T3.8/61 kt.

Makes me wonder how many storms have been significantly underestimated without recon, even in the satellite era.

[aspen]

That <-80C perfectly circular CDO with a pinhole starting to show up on visible is a terrifying sight. Imagine how nuts Delta is going to be once that clears out...

[Shell Mound]

OHC is actually slightly higher closer to the Yucatán. Absolutely bonkers rocket fuel for the next 18-24 hours.
https://rammb-data.cira.colostate.edu/tc_realtime/products/storms/2020al26/ohcnfcst/2020al26_ohcnfcst_202010060600.gif

Some “good” news: models show relatively high background pressures in the N Gulf, meaning smaller-than-average size, hence lower surge. Add lower OHC, mid-level shear, and continental dry air. This system will be rather tame vs. other N-Gulf hurricanes, especially in terms of fetch, given the high background pressures (= reduced fetch). Furthermore, given the other negative factors, Delta is likely to weaken significantly prior to landfall on the N Gulf Coast. While a Category-5 impact to the Yucatán Peninsula is quite plausible, I can’t envision anything stronger than a weakening Cat-2 in Louisiana. But time will tell.

[NotoSans]

Recon confirms a high-end category 2 hurricane, but the latest Dvorak estimate from ADT is still T3.8/61 kt.

Makes me wonder how many storms have been significantly underestimated without recon, even in the satellite era.

Objective Dvorak can significantly differ from subjective ones. This is a clear embedded center pattern which would yield T5.0/90kt, quite consistent with recon.

[ElectricStorm]

That <-80C perfectly circular CDO with a pinhole starting to show up on visible is a terrifying sight. Imagine how nuts Delta is going to be once that clears out...

The HWRF showed that pinhole a couple days ago... It has been pretty impressive with storm structure this year.

[plasticup]

I know this is a debatable topic but rapidly deepening TCs increase odds of triggering earthquakes.
I have seen it many times in the Carb and a couple along the east coast.
Very close to the fault line.
Just saying.

https://i.imgur.com/D8BRhKc.png

I’ve never heard of this. Is there actually some kind of causality link here or is it more a third variable problem?

The theory I have heard is that the massive water and atmospheric displacement shifts enough mass to destabilize the fault line. It is a weak correlation at best, if it exists at all. But it is certainly an interesting theory.

[us89]

 https://twitter.com/TropicalTidbits/status/1313471186127519744