Questions about Rainfall Not Directly Associated with a Tropical Storm.

[Tullioz]

This is not the best example, but today we had a weak tropical storm pass through the Philippines. The heaviest rains were found well north and east of the center of circulation. While the exact center is hard to define at this point, it is somewhere west of the main islands roughly where the red circle is based on information provided by the JTWC and my best estimate.

My questions are, what would be the cause of the heavy rain continuing well to the east of the storm center, and is there a technical term for this? 

https://www1.pagasa.dost.gov.ph/index.php/2-uncategorised/2700-radars

 

Link to Satellite (Time sensitive)

http://www.ssd.noaa.gov/PS/TROP/floaters/02W/flash-ir-short.html

 

 

[LTC]

The rain should be to the East, that is where southerly air is riding up which in turn leads to convection. Over the more open water it can pick up even more moisture leading to more intense convection. It looks like the system is mature but still has a lot of energy at its disposal. The extra convection may be helped by upper level PVA from a shortwave or a jet streak, frictional/coastal convergence, orographic lift (depending on the terrain), a sea-breeze effect (could prevalent on the East as there is a mean zonal Easterly flow above), low-level shear, low-level warm thickness advection, anything  that would enhance upward motions. Check all the maps carefully. Familiarize yourself with the patterns.