Tropical Storm Dolly Remnants

[vortex95]

22 hours ago, cptcatz said:

Dolly still looking voluptuous at this ripe age of hers. 

I feel like models have no idea what's going on. Same with NHC. How can this possibly only have a 0%/10% of becoming a TC?

Yes, the convective mass is impressive w/ very cold cloud tops. but it is amorphous and rapidly pulsing.  This indicate lots of shear and/or dry air, which promotes regular severe convection, but it detrimental to TC formation/development.  We saw this w/ Bertha when it was on the LA coast and intense mass of convection well S due to strong shear.

Look at the loop attached for Ex-Dolly this morning.  The convection is "ripping" linearly E to W on a trough line.  No circular motion or banding at all.  That is not a sign of overall intensification as a TC.  Sure, there are gale force winds easily in that severe convection, but that is mesoscale and transitory, not pressure gradient driven on a larger-scale, which what you look for a TC.

Basically, it does not fit the requirement of a TC, which is a coherent, closed low-level wind center w/ persistent convection.  Yes, you can still have shear and dry air present and have a TC, but this is not the case here b/c synoptic conditions are so unfavroable.  It as a strong tropical wave, it can thrive when it comes to intense convection, but lack organization to fit the definition of a TC.

Generally you do not want to see rapid blow-ups of convection for TC development/intensification b/c it often pulses down quickly and leaves cooler, low-level outflow soundbites from collapsing convective towers (including downbursts), that radiate away in a divergent pattern, which prevents or weakens any low-level circulation.  You see this is often in sheared systems in the form of fine-line line outflow boundaries moving away from the center on VIS.

Circular banded convection around a center that has not as cold cloud tops is much better to see on satellite for a TC than what we see for ex-Dolly now.
 

[jconsor]

As others have been discussing, Dolly has proven quite resilient vs. model expectations, with the recent 'explosion' of convection seemingly aided by the diffluent, highly sheared flow.
Surface obs from the Leeward Islands in the NE Caribbean have been quite interesting.   I agree with @vortex95 that it's pretty clear Dolly doesn't meet the criteria for a TC, but it is not far off IMHO.

Thread here:

https://x.com/yconsor/status/2094029423624310857