I hope I properly understood what you were looking for, as you highly likely know already we have the forecast maps on weather.gov that show the areas of high and low pressure as you mention, sure. But you say you want to look at the air masses as well, well there does exist a public frequently updated animation loopable satellite imagery site from NOAA, which is imaged from their satellites called GOES East (newer) and GOES West.
If you visit
https://www.star.nesdis.noaa.gov/GOES/index.php you will find the aforementioned site, from which you can select a region on the map or on the left, cover multiple regions (hovering over will highlight bigger portions of the map if it covers more). Once selected, you can select the band at which you wish to view the imagery, in this case for airmasses we are interested in IR and WV. Now if you don't know how to read it, under the imagery (on the animation loop page in my experience), you will find a short description of how it can be read, as well as a link to a much more detailed PDF guide on how to read air masses from that imagery. As an example here is the last 48 images from GOES East with CONUS being the view range, animated, with the aforementioned guidance below it, in RGB Composited IR and WV:
https://www.star.nesdis.noaa.gov/GOES/conus_band.php?sat=G16&band=AirMass&length=48Apologies if you already knew about this, just thought I'd throw it out there.