Jangmi fades after ET
The last warning for Jangmi from JTWC was issued at 21Z on the 30th of September. Jangmi had
max sustained winds at 35 kts with gusts to 45 kts. As it moved into the midlatitude westerlies it completed
extra-tropical transition. Attached is an IR image with overlayed divergence and upper-level AMVs. The animation ends on 13Z on October 1st:
You can see how sheared the system is and that it’s lost any symmetry. According to the GFS phase diagram Jangmi has already fully undergone extra-tropical transition. It still has some anticyclonic outflow to the south, but it is impeded to its north from the midlatitude jet.
Unfortunately, the C-130 has finished flying for the experiment and the P-3 has been down due to an AC problem. But, we will have flight data from the Falcon (and perhaps the DOTSTAR too) which will be vital for AMV validation.
Attached is the planned route for the Falcon at 00Z on the 1st of October, plotted over ECMWF forecast upper-level winds and low-level vorticity:
As you can see they are attempting to sample Jangmi’s outflow and interaction with the midlatitude jet. The model output shown above agrees fairly well with the 200 hPa streamlines from the AMVs
And what about future development?
The ECMWF does not do much with it in terms of development. The GFS hints at Jangmi merging with another disturbance and developing something downwind. The NOGAPS and Met Office model hint at something as well. These should be well out of range for the research aircraft, but perhaps the data we’ve obtained from the experiments will help downstream forecasts.
Tags: Extra Tropical Transiton, TCS047, validation