High-pressure system, or anticyclone. Which one do you use?
From November 6-9, we had highs of 10.6, 14.3, 15.6, and 7.3. Each was at least a few degrees above average. We even had the very rare 5 degree November low on the 7th! That low of 5.2 collected us a record for the highest low.
The setup for this was a naughty little high to the south and low to the north. The high created a large ridge, and also pushed warm air up to the northerly low. This created very warm temperatures for a few days.
The heat wave was also odd because it was bordered by short cold waves on either side, which both brought highs to near 0.