John Cooper created this SPI style variant. He included the Blitzkrieg Modular System, and has added weather cards. We are publishing all his material on this variant as a complete set - including three charts, weather cards, and 7 sheets of double sided counters (or chits, since this is an SPI rendition of the game).
For the Blitzkrieg game, this is the full monty. All you need from the original game are the rules, charts, and the die - which you probably already have (or can download).
Mr. Coopers notes are here - LINK