Could you take a look at this link and tell me what I'm looking at?
http://www.wunderground.com/modelmaps/maps.asp?model=NAM&modelrun=0&map=SURPRE&time=54&model=NAM&domain=US
That's the North American Model (NAM). Typically a good short range (48-60 hours or less) model... but, not one of the better ones when it comes to hurricane forecasting.
That map is an overlay of precip totals for a 3hour period, as well as an identifier of pressure. This shows the storm moving into Mexico... which you can see on the larger version from NCEP.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/images/nam_p06_054m.gif
