Confirming the polling we have seen and the analysis of independent analysts such as Larry Sabato, the Cook Report (subscription required) tells us:

For the first time, our internal race-by-race model estimates a GOP gain of over 40 seats. We are revising our House forecast to a Republican gain of at least 40 seats, the minimum to give them majority status, and very possibly substantially more. …

Even Democrats in districts that gave President Obama 50 to 60 percent of the vote can’t be considered safe; in fact, as Obama’s approval has slid disproportionately in swing seats, many are in tough predicaments. By the time we release new House ratings this week, eight Democratic open seats will be in the Lean or Likely Republican columns, 45 Democratic seats will be in the Toss Up column, and 30 seats will be in the Lean Democratic column, for a total of over 80 Democratic seats at substantial risk.

This should come as no surprise, actually, if you have been following the generic congressional polling. With the addition of Rasmussen (GOP +12) and CNN (GOP +7), the RealClearPolitics.com average now shows an 8.4-percent advantage for the Republicans. Get out your thesaurus (wave, a tsunami, deluge) — there are a lot of Democrats who are about to get swept out of Congress.