Here's what to expect when Sandy hits

(CNN) -- With Hurricane Sandy lurking offshore Sunday night like a heavyweight boxer winding up a wallop of a punch, the CNN Weather Unit forecast that the massive storm will make landfall late Monday near the Delmarva Peninsula and southern New Jersey. Delmarva -- which gets its name from the three states that occupy parts of it: Delaware, Maryland and Virginia -- was just one of many population centers along the East Coast where residents were bracing for or backing away and heading inland from anticipated walls of wind and water. Keep a hurricane preparation checklist What to expect: Strong winds Hurricane-force winds will pummel the coasts of Delaware, New Jersey and New York state, with tropical-storm-force winds stretching from North Carolina all the way to Maine. Likely immediate impact: downed power lines and extensive power outages. Storm surge The highest storm surge will occur along the coasts of New Jersey, New York and Connecticut, especially where water funnels into New York Harbor and Long Island Sound. Immediate impact: coastal flooding and beach erosion. Flood-triggering rainfall Heaviest rainfall of up to 8-12 inches will be likely on the Delmarva Peninsula and in New Jersey. Immediate impact: Cities such as Dover, Delaware; Baltimore, Washington and Philadelphia could see significant flash flooding. Snow Extreme snowfalls totaling several feet will be likely in the Appalachian Mountains of West Virginia and to a lesser extent into portions of Pennsylvania and Virginia as well. Flight delays With major airlines canceling many flights even ahead of the story, air travel will be extremely difficult for all of the major Northeastern cities from Washington through Boston both Monday and Tuesday. Impact: The ripple effect on air travel will be felt worldwide as flights arriving and departing will be canceled or severely delayed. Timing Conditions will be deteriorating along the Mid-Atlantic into the Northeast through the day Monday. Landfall will occur Monday evening into overnight, and storm surge likely will peak around the evening high tide (remember Monday's tides are already the largest of the month due to the full moon). On Tuesday, rain and snow will continue for much of the area and surf will remain very rough as the center of the system slowly drifts northwards into Pennsylvania and New York. Delayed impact Because of the size of this system, many impacts will be felt far from the center. For example, large waves and surge will be felt in eastern Canada and along the shores of the eastern Great Lakes. Also, when Sandy transitions from hurricane or tropical storm to "post-tropical storm," it does not mean that the storm has weakened or that the threat is any less.