Right now, we are in the warm ridge position (left image) but tonight and tomorrow the transition from ridge to trough will occur resulting in rain (middle image). The trough will lift out and a ridge will move in by next weekend (right image), only to pave the way for another trough to move in. (See pictures for illustration of why I am calling it the Roller Coaster. The ups and downs of the 500 mb height pattern resemble a roller coaster.)
Each time the trough moves in precipitation occurs. Currently, in this pattern that precipitation is overwhelmingly in the form of rain.
Changes will occur as we head into the first week of February. A 3 - 4 week period of serious cold and stormy weather could be coming.