Natural Gas Spreads and the Cost of Full Carry

This is the Nov12 / Jan13 NYMEX natural gas spread during today's EIA inventory report.  The annualized spread differential for this pair is about 19.5 cents per month.  According to some physical traders I spoke with, the cost of carry for this type of trade is about 10 cents per month.  Despite the massive premium available for those who are able to take delivery, inject into storage, withdraw from storage, then sell it against the Jan13 contract, this spread maintains its elevated state precisely because storage capacity for the winter months is so constrained.