Here's a good visualization of the TROWAL Mitch was talking about.
Now the TROWAL exists at many levels (it's a trough of warm air aloft after all), sloped on either side, but a good proxy is usually theta-e on the 700 mb surface. You can see the warmer theta-e temps curling cyclonically around the low (warm conveyor should peel off to the east remember). Heavy precip occurs on the west side of this axis, so I overlaid the regional radar to highlight that is in fact occurring.