ATL: ETA - Post-Tropical - Discussion

[aspen]

So far, no update from the NHC that they’ll initiate advisories at 5. They might not upgrade this to a TC for this advisory.

[NDG]

The 5 day forecast track is going to be interesting, I am sure the cone will cover a wide range after 72 hrs.

[Aric Dunn]

Good vorticity up through the column.

once deep convection begins to build it wont take long to rapidly intensifiy.

[Loveweather12]

https://i.postimg.cc/4dJ0MbfT/image.png
https://i.postimg.cc/JhPwRddh/image.png

You know it’s 2020 when ASCAT fails to detect a budding hurricane and the EPS caves to the GEFS in the short to medium term...as we are witnessing.

EPS caving?
WhAts going on? Didn’t see the latest model?

[aspen]

I’m thinking no upgrade at 5. The NHC would’ve announced at 4 that advisories would be initiated, and it’s 4:25.

EDIT: and they announced it as soon as I made my post

[cycloneye]

 https://twitter.com/NHC_Atlantic/status/1322635479737458688

[shiny-pebble]

I’m thinking no upgrade at 5. The NHC would’ve announced at 4 that advisories would be initiated, and it’s 4:25.

EDIT: and they announced it as soon as I made my post

They must have read your post

[SFLcane]

Let’s see if the nhc disregards the gfs.

[SFLcane]

 https://twitter.com/johnmoralesnbc6/status/1322636142186029056

[fox13weather]

The requirements for a PTC advisory are that there is a high chance of development (check) AND that the potential storm is within 48 hrs of impacting a coastal region that the NHC warns for (nope). Looks like it will reach the coast of Nicaragua Tuesday evening. Therefore, about the earliest we could expect a PTC advisory would be tomorrow late afternoon. However, if you're curious what the NHC track would look like, it would look just like the consensus model (TVCN):

http://wxman57.com/images/TVCN.JPG

Note that the TVCN indicates a significant slowdown just before landfall. 96L may well loop along the coast of Central America and not move far inland at all.

The current rate of intensification means that 96L (Eta) is less likely to move well inland before stalling, looping offshore, and eventually heading northward.

I’m already thinking this could well become a high-end Cat-4 or even low-end Cat-5 before hitting Cabo Gracias a Dios, stalling, and then entering the GoH.*

*Gulf of Honduras

(At any rate, this won’t weaken much, if at all, due to the brevity of its landfall on the relatively flat, marshy Miskito Coast, near the Nicaragua–Honduras line.)

Don’t be shocked if both Central America and Cuba/Florida face the possibility of multiple Cat-4+ landfalls in association with 96L (future Eta).

"Don’t be shocked if both Central America and Cuba/Florida face the possibility of multiple Cat-4+ landfalls in association with 96L (future Eta)"

Ya, I suppose. At this point, multiple outcomes are possible and what you are speculating is a worst case scenario that includes many moving pieces coming together perfectly. Could it happen? I guess. There are also many other plausible outcomes, but as is usually the case here...lets wishcast the worst possible scenario....


(At any rate, this won’t weaken much, if at all, due to the brevity of its landfall on the relatively flat, marshy Miskito Coast, near the Nicaragua–Honduras line.)

How do you know? You are sure at this point that it will end up along the Nicaragua-Honduras line even though the first advisory has not been issued yet?

[Hypercane_Kyle]

I honestly cannot believe we're about to see Tropical Storm Eta.

Just nuts.

[Shell Mound]

The requirements for a PTC advisory are that there is a high chance of development (check) AND that the potential storm is within 48 hrs of impacting a coastal region that the NHC warns for (nope). Looks like it will reach the coast of Nicaragua Tuesday evening. Therefore, about the earliest we could expect a PTC advisory would be tomorrow late afternoon. However, if you're curious what the NHC track would look like, it would look just like the consensus model (TVCN):

http://wxman57.com/images/TVCN.JPG

Note that the TVCN indicates a significant slowdown just before landfall. 96L may well loop along the coast of Central America and not move far inland at all.

The current rate of intensification means that 96L (Eta) is less likely to move well inland before stalling, looping offshore, and eventually heading northward.

I’m already thinking this could well become a high-end Cat-4 or even low-end Cat-5 before hitting Cabo Gracias a Dios, stalling, and then entering the GoH.*

*Gulf of Honduras

(At any rate, this won’t weaken much, if at all, due to the brevity of its landfall on the relatively flat, marshy Miskito Coast, near the Nicaragua–Honduras line.)

Don’t be shocked if both Central America and Cuba/Florida face the possibility of multiple Cat-4+ landfalls in association with 96L (future Eta).

"Don’t be shocked if both Central America and Cuba/Florida face the possibility of multiple Cat-4+ landfalls in association with 96L (future Eta)"
Ya, I suppose. At this point, multiple outcomes are possible and what you are speculating is a worst case scenario that includes many moving pieces coming together perfectly. Could it happen? I guess. There are also many other plausible outcomes, but as is usually the case here...lets wishcast the worst possible scenario....

(At any rate, this won’t weaken much, if at all, due to the brevity of its landfall on the relatively flat, marshy Miskito Coast, near the Nicaragua–Honduras line.)

How do you know? You are sure at this point that it will end up along the Nicaragua-Honduras line even though the first advisory has not been issued yet?

1) Short-term intensity trends and rapid organisation vs. most models other than HWRF, along with very conducive conditions ahead
2) EPS/GEFS converging on a possible loop and/or stall over coastal Central America, near the Nicaragua-Honduras, based on coordinates
3) Likelihood that the first trough prevents a track well inland over CA, while the presence of ridging precludes a track well offshore
4) Climatological influences as well as the influence of a second trough in the medium to long range suggest an eventual turn northward

[ElectricStorm]

Well this will certainly be an interesting first forecast. I'll guess they'll be showing a Cat 1 into CA with it starting to recurve at the end of the forecast

[Kazmit]

NHC says peak of 75 kts

[ClarCari]

75 kt peak already oh deeaarr here we gooo.....

[Shell Mound]

Well this will certainly be an interesting first forecast. I'll guess they'll be showing a Cat 1 into CA with it starting to recurve at the end of the forecast

After that time, however, there is
significant divergence in the models. For example, the ECWMF and
its ensemble members continue on a faster westward motion across
Central America, while the GFS and its ensemble members stall the
system over the western Caribbean Sea through day 5. Given this
discrepancy, the NHC official track forecast shows a slow motion on
days 3 through 5, and brings the cyclone's center slowly across
northern Nicaragua, more or less in line with the multi-model
consensus aids. This forecast is of generally low confidence,
however, and significant changes could be required in later advisory
packages depending on model trends.

[edu2703]

First cone. Peak forecast at 75 knots

[ClarCari]

Well this will certainly be an interesting first forecast. I'll guess they'll be showing a Cat 1 into CA with it starting to recurve at the end of the forecast

You nailed it!

[AutoPenalti]

Ah yes, the generally low confidence forecast.

But at least there’s general agreement that this will intensify pretty quickly as the models suggest.

[fox13weather]

Note that the TVCN indicates a significant slowdown just before landfall. 96L may well loop along the coast of Central America and not move far inland at all.

The current rate of intensification means that 96L (Eta) is less likely to move well inland before stalling, looping offshore, and eventually heading northward.

I’m already thinking this could well become a high-end Cat-4 or even low-end Cat-5 before hitting Cabo Gracias a Dios, stalling, and then entering the GoH.*

*Gulf of Honduras

(At any rate, this won’t weaken much, if at all, due to the brevity of its landfall on the relatively flat, marshy Miskito Coast, near the Nicaragua–Honduras line.)

Don’t be shocked if both Central America and Cuba/Florida face the possibility of multiple Cat-4+ landfalls in association with 96L (future Eta).

"Don’t be shocked if both Central America and Cuba/Florida face the possibility of multiple Cat-4+ landfalls in association with 96L (future Eta)"
Ya, I suppose. At this point, multiple outcomes are possible and what you are speculating is a worst case scenario that includes many moving pieces coming together perfectly. Could it happen? I guess. There are also many other plausible outcomes, but as is usually the case here...lets wishcast the worst possible scenario....

(At any rate, this won’t weaken much, if at all, due to the brevity of its landfall on the relatively flat, marshy Miskito Coast, near the Nicaragua–Honduras line.)

How do you know? You are sure at this point that it will end up along the Nicaragua-Honduras line even though the first advisory has not been issued yet?

1) Short-term intensity trends and rapid organisation vs. most models other than HWRF, along with very conducive conditions ahead
2) EPS/GEFS converging on a possible loop and/or stall over coastal Central America, near the Nicaragua-Honduras, based on coordinates
3) Likelihood that the first trough prevents a track well inland over CA, while the presence of ridging precludes a track well offshore
4) Climatological influences as well as the influence of a second trough in the medium to long range suggest an eventual turn northward

We will see.