Archive for October, 2008

TCS049…the next TPARC target

Thursday, October 2nd, 2008

TCS049 is a potential flight target for today. If they flew, the P3 would fly from 21Z on the 2nd - 05Z on the 3rd.

The animation shown below gives some sense of its structure:

It has some decent convection to the north and moderate upper level divergence.  You can see signs of anticyclonic outflow to the northeast of the storm. You can also see a fairly strong TUTT low to the storm’s northeast limiting its development.

What about a low level center? The attached image shows the quikscatt analysis and available surface obs:

You can see a cyclonic circulation on its northeast side, but there is no sign of westerly winds on the east side.

And the shear?

The image above, valid at 11:30 Z on Oct. 2, 2008 shows the shear surrounding TCS049. You can see the southerly shear from the associated TUTT cell to its northwest and the ridge to its east. The shear is currently preventing significant development.

And for its future?

The EC model is the only one that really does something with this system. It sort of splits, with one system moving north and quickly recurving and a second , weaker system moving westward towards the Phillipeans.

Both of those happen in the long term though. It does not seem to be a system with a bright future.

Links:

ECMWF,Met Office,NOGAPS,GFS

Jangmi fades after ET

Wednesday, October 1st, 2008

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.