Yes, high pressure systems do bring sunny, rain-free weather, but when they are still to the west of a given place, they go along with cool/cold weather, while when they are positioned a little to the east of the place the sunny weather is accompanied by above average temperatures as well. When you are right in the middle of a high, the temperature tends to be average or slightly higher. It depends partly on where the air mass associated with the high came from. In winter, some of these highs come southward out of Canada/Alaska, and they are cold. Others come from the west, from the Pacific, and are more moderate. We also need to clarifiy whether we're talking about high pressure at the surface, or higher up in the atmosphere, such as at 500mb (about 18,000 feet altitude). These high pressure systems tend to tilt to the west with height, so when the high is right over you at the surface, it may still be a bit west of you in the upper atmosphere. There is an upper air pressure pattern associated with strong El Nino events in winter over the US. It consists of a large high pressure center over south-central Canada, the Great Lakes, and extending westward to the northern Rockies and eastward to northern New England. To the south, and covering much of the southern tier of states, pressure is lower, as might be expected with the enhanced extended Pacific jet during El Nino that brings increased storm activity along the southern tier. The pressure pattern typical for El Nino shows up in a long-period average (such as a 2- or 3-month average), and does not apply to shorter time-scales like weekly. Weekly patterns may have a lot of variety and not look like the El Nino pattern. That may be what is happening now, with a high pressure ridge over the western states (SOCAL) and a trough over the eastern states. This pattern may only last several days, or it could go on for a whole week or even more. But our best bet for the whole winter, averaged, would be for lower pressure over SOCAL (and above average rainfall), and higher pressure over the northern tier of states, and a tendency for below normal precipitation in many of the subregions up there, and also above-average temperatures.

During weaker El Nino, and sometimes even regardless of El Nino, there is a tendency for higher than average pressure over the western states and lower pressure over the eastern states, associated with the so-called PNA (Pacific/North American) pattern. During strong El Nino, the PNA pattern tendency becomes the so-called TNH (tropical/Northern Hemisphere) pattern, a clockwise-rotated version of the PNA pattern, with the high over southern Canada/Great Lakes and low over the southern tier of states in association with the enhanced and extended Pacific jet.