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.