Hi Bob,
As Robert mentioned and Tim suggested, use of a warming filter with a polarizer can be very valuable. That is why the filter makers have come up with warm polarizing filters. That way there are fewer air/glass interfaces. So rather than using the warming filter and a polarizer as Tim has mentioned, it is preferable to use a single warm polarizer such as the Tiffen warm Polarizer (Tiffen 812 + Polarizer as Robert has mentioned. All the major filter makers including Tiffen, Hoya, B + W, Heliopan, and Singh-Ray have their own versions of these filters. I have the Tiffen, the older Singh-Ray and the new Singh-Ray Lighter Brighter Warm Polarizing filter. The new Singh-Ray filter is expensive, but allows much more light through and as a result has less exposure correction. This is particularly valuable with slower large format lenses and when focusing with the filter on the View Camera.
Rich