TCS037 weakens, TCS033 becomes Tropical Depression 15W.
IR animation and 14z upper-level AMVs for Tropical Depression 15W. AMVs valid 14z September 08, 2008. It's fairly good, organized convection. Quickscatt is showing a closed circulation and the upper level AMVs shows a solid anti-cyclone over its center.
TCS037 has weakened appreciably over the past few days while TCS033 has now organized, strengthened and become a depression.
Below is the overview plot showing a water-vapor image and upper-level AMVs.
TCS037 has lost most organization. As you can see in the overview, there is a fairly strong upper-level low just to the southwest of 37. Although it has some upper-level divergence and outflow, it is also in a very narrow region of low shear, surrounded by strong shear. Perhaps this interaction with the upper-low is inhibiting it’s development.
Our focus for the next few days will be TCS033: now named Tropical Depression 15W.
Attached below is the 14Z AMVs and IR animation for Tropical Depression 15W.
IR animation and 14z upper-level AMVs for Tropical Depression 14W. AMVs valid 14z September 08, 2008. It's fairly good, organized convection. Quickscatt is showing a closed circulation and the upper level AMVs shows a solid anti-cyclone over its center. Also shown is the JTWC forecast track and forecast error.
15W has a narrow shear minimum over it’s center, but is surrounded by higher shear values to it’s north and south as seen in the plot below:
IR image, upper-level AMVs and deep-layer shear for 15W.
The shear values shown are in opposite directions to the north and to the south of the storm, perhaps suggesting the shear is due to the strength of the outflow, rather then the envirnoment.
The next post will focus on its track and forecast.