If you have a lake in mind I’d stop at a local bait shop or two and ask how the fishing has been on that lake and where some of the action has been found already. Crappies won’t move far from the last point of activity just because a cold front rolls thru, but they will probably be found deeper. If shallow bays or shorelines had afternoon activity prior to the front, I’d look at the slightly deeper water adjacent to these locations and check the entire water column from bottom to top. The deep water is a crappie’s post front security water, but they can be found anywhere top to bottom in it. Rely on electronics to tell you where to find them depth-wise.
Again asking at a baitshop that caters to the lake of choice I’d ask what has been the bait of choice and then start with it. Personally I do not use live bait on crappies and as close as I will get to it is Gulp minnows or PowerBait minnows. My preferred bait is plastic though and in cold front conditions I slow it up a little and often go to a less aggressive profile, but I seldom go to smaller baits with Gulp being the exception: if I have been catching crappies on a 1-1/2″ paddletail I might switch to a stinger-type bait of the same length. I’m more willing to play the color switch game in post cold front conditions: what worked two days ago might hand you a skunk. The biggest ace in the hole is staying flexible and if fish are marked but tight lipped the Gulp will come out. I like the 1″ minnows in water temps much under 60 degrees and this minnow will work great right down in cold water too. Much above 60 degrees and I’ll use the next size larger Gulp minnow or power minnows.
Post cold front crappies do not stop eating but they do change how they eat. Their feeding windows may close up and shorten in duration. Instead of popping a bait good they may simply slide up to it and suck it in gently, much like a winter crappie. Cold front crappies can be notoriously depth specific and may hit or be located in as small as a couple foot band of water, hence a float can be your best buddy. Little things can make the difference to these fish and a clear line can be a huge advantage but let the fish dictate whether they’ll hit a braid or colored line even with a leader.
This post front time is a great time to fish vertically in and amongst the branches of sunken wood or limbs or right up tight to the outside edges of weed lines or right down on top of the weeds themselves to coax crappies out. Wind can be a double edged sword if fishing this period and in sunken structure as boat control has to be spot on or you’ll be snagged up a lot. On the other edge is the refraction from the wave activity to help hide your boat’s shadow and outline.
Find out where the action has been and head right to that area and start snooping. If this lake has just seen ice out those crappies will be ready for meat instead of bugs so they’ll work plastics for you but be ready to switch colors and profiles until you hit on one that works.