Harrier, here's Xaxero's GRIB viewer:
http://www.sea-tech.com/windplot.htm
There are others, including free products. I'm confused by WindPlot's mention of the internet since mere mortals like us don't have the ability to access the internet offshore. Hopefully Xaxero's viewer works without an internet connection.
I request the weather file(s) by sending an e-mail via satphone to SailDocs, a free service. Instead of using a separate GRIB viewer like WindPlot, my charting software* formats the e-mail, using the lat/lon range I format on the chart. It puts that e-mail into the satphone's "queue" and it is sent when I turn on the phone. SailDocs' computer creates the weather file, attaches it to an e-mail and sends it back to me, often before I can even hang up. Sometimes I have to wait a few minutes and reconnect. Then I download it to the charting software and it appears as an overlay on the chart. This is a simplified explanation - the actual steps depend on the software you're using.
You can set this up and test it at home, then substitute the satphone when you're on the boat. I assume you could also substitute an e-mail capable DeLorme unit.
I'm traditional in the sense that I use a Garmin chartplotter as my primary means of navigation (paper charts are also desirable). The Garmin is designed for use on a boat, it also shows the data from my instruments (like AIS targets, depth, etc.) and it will be there if my iThing (or your laptop) gets wet or goes flying across the cabin and busts into pieces.
But for this GRIB-via-satphone process, I use *iNavX as my charting software on my iPad and iPhone. Either iThing connects via wireless hub to the satphone to send and receive the e-mails. The new Iridium GoPhone combines the phone and wireless hub - I have an older Iridium AxcessPoint as the hub and I borrowed a satphone for the last Hawaii trip (thanks again, John M!)
"Parts is parts" - I edited this post several times trying to make it more clear. Dirk, a jam session with this stuff is a good idea.