ATL: INVEST 94L - Discussion

[Aric Dunn]

Yeah, definitely a little more going on here than the models are showing..

Continues to improve today..

[LarryWx]

Yeah, definitely a little more going on here than the models are showing..

Continues to improve today..

Based on the model consensus of strong E US/W Atlantic ridging being forecasted for the 7-10 day period, 94L would actually be more concerning to me from a CONUS perspective than the wave now moving off Africa. So, any unexpected genesis of this needs to be monitored extra closely for the CONUS.

[Aric Dunn]

Yeah, definitely a little more going on here than the models are showing..

Continues to improve today..

Based on the model consensus of strong E US/W Atlantic ridging being forecasted for the 7-10 day period, 94L would actually be more concerning to me from a CONUS perspective than the wave now moving off Africa. So, any unexpected genesis of this needs to be monitored extra closely for the CONUS.

Agreed. The models runs from a few days ago were rather concerning. Especially the few gfs runs that made it a carrib runner than turning into the gulf

[northjaxpro]

I agree. The recent trends with 94L have been very concerning indeed

[GCANE]

Convection expanding all morning in area and intensity.
Now seeing back-to-back vortical hot towers firing east to west.

[GCANE]

MIMIC-TPW indicates CoC is moving WSW or SW

[crm6360]

Convection expanding all morning in area and intensity.
Now seeing back-to-back vortical hot towers firing east to west.

Question - are towers ever not vertical and hot? Do we ever get cold horizontal towers?

[Cat5James]

Convection flaring in the latest frames on Satellite Imagery... not counting this wave out

[GCANE]

Still connected to the ITCZ, looks like a track to the SW is probable at the moment.

[Nederlander]

Convection expanding all morning in area and intensity.
Now seeing back-to-back vortical hot towers firing east to west.

Question - are towers ever not vertical and hot? Do we ever get cold horizontal towers?

vortical ... not vertical, even though they are vertical

[GCANE]

Convection expanding all morning in area and intensity.
Now seeing back-to-back vortical hot towers firing east to west.

Question - are towers ever not vertical and hot? Do we ever get cold horizontal towers?

I never heard of a cold tower.
Hot tower was coined from a group of researchers in the 60's.
It is distinguished from normal cumulus nimbus in that they have very high updrafts and hit the top of the troposphere.
An anvil cirrus cloud then is then created.
It looks much like an atomic bomb.
The key feature is that it has very high rain rate which leads to latent heating of the mid-layer of the troposphere.
This in effect helps to create a warm core.
In some cases the updraft is so fast, it creates a horizontal spin due to Coriolis effect. This is a vortical hot tower.
This spin actually couples to mid-level vorts and can drive the vort to the surface.

[Aric Dunn]

There is definitely two vorts that very noticeable.

One that has tucked in under the convection to the north. And the other is partially exposed to east. .. very clear swath of west winds.

Looks like the vort that tucked in under the convection is firing more convection and the curved inlfow is expanding.

The other vort will probably get stretched out assuming convection keeps building with the other one.

[GCANE]

Shear forecast per latest GFS

Now: 5 knt
48 hr: 15 knt
72 hr: 4 knt
96 hr: 12 knt

[GCANE]

Surface winds on the NE of the CoC seem to be speeding up.
NW of the CoC, they seem to be curving more into the CoC.
Looks like its ramping quickly.

[SconnieCane]

Seems some of us (and NHC with its drastic lowering of probabilities) may have got a little too impatient with this invest.

[GCANE]

Winds shifted to the SW on a buoy SE of the CoC.
https://www.ndbc.noaa.gov/station_page. ... tion=41026

[Patrick99]

Seems some of us (and NHC with its drastic lowering of probabilities) may have got a little too impatient with this invest.

I feel like there is always this tendency here to either want to ramp it up to a Cat 5 in a day and a half, or call for its outright dissipation - when the reality is typically somewhere in between. I probably won't ever forget those who were thinking Dorian would flat-out spin down into nothing, in the Caribbean.

[toad strangler]

 https://twitter.com/dadabuh/status/1171036021464678406

[mpic]

Do NOT want a hurricane, but just a little tropical wave wishcasting for East Texas. Burn bans up all over. Need some relief.

[Aric Dunn]

https://twitter.com/dadabuh/status/1171036021464678406

Although that does happen where the first wave fails..

Its also just as common for the first to develop.. dorian was the leading wave.

Just have to keep watching it.