okay, looks like i'm going to get my sw caribbean feature. and 27 shouldn't be able to stop it, which i was wrong about the other day. it's becoming too well-defined. no dvorak classification on it but i'd guess it's a 1.5. you can SEE the low cloud motions swirling around it's broad center.. the little feature that cycloidally looped off the nw colombia coast the other day appears to be what this thing is focusing around. appears to be moving slowly... as all that anticyclonic ridging aloft evacuates thunderstorms and causes pressures to fall dynamically.. it should tighten up and become a classified system tomorrow. as it becomes a defined system it should begin to move westward... and end up moving ashore in nicaragua later on thursday i'm guessing. it's very broad, so it might still be acting up on the pacific side.
to the east td 27 is getting under progressively less shear. its proximity to the developing system to the west should make continued development slow. the recon mission today found 41kt flight level winds, which usually equates to a tropical storm.. but they've gone on the side of conservatism. center is poorly defined, partially due to its speed. the strong easterly flow to the north is pushing it right along, but even so shear is decreasing and the center seems to be clinging to and refiring convection to the east. ssd has rated it a 2.5 tropical storm for three consecutive cycles... collectively the evidence for upgrading it seems to be there. the convective signature should become much clearer some time overnight, even though the nhc advisories have mentioned it 'needing to survive the next 24 hours shear' in every one of the recent advisories. the upper cloud motions and rate of shear reduction suggest to me that it'll fnally get through pretty soon, as well as the gfs termination of the westerly 200mb vectors just beyond its location. another recon should be in tonight, so we'll know one way or another. as it goes further west it should still develop more or less along the lines of the earlier idea... perhaps a little less so, due to competition with the other system. the other system should cross central america, however, while 27 should get hung up by height falls to the nw, giving it an eventually different fate. the global consensus in the long term turns it ne after a stall, kinda like what i was thinking... only the tracks have now shifted further south, closer to eastern cuba. looks about right.
in the middle to long term, other things are showing up. the deep layer system forecast to dig in northeast of the caribbean has a non-development profile in the models, but only a little change and the potential exists for a drill-down. around ten days out, with a deep trough in the east, a block near greenland, and a corresponding deep layer system in the eastern atlantic from the strong nao-negative configuration... whatever is cut off over there may also make a run at hybrid development. the shear profiles from the extremely amplified pattern could potentially support such an outcome.
i'll throw in that the current severe weather tonight appears to be right on with bastardi's forecast step-down to cold pattern. the models are showing more cold air and a deep trough in the east next week...as a matter of fact the euro and gfs are showing systems that could produce winter weather around thanksgiving in parts of the southeast. needless to say i'm interested. the models haven't converged yet on particular shortwave features, but the basic pattern setup appears to be coming together. climatological fall is going out with a bang around here, looks like. something has to balance all that activity in the tropics.
HF 2355z15november