Intense continental cyclogenesis occurred during the Ohio Valley Blizzard of 1978. Notice how this system, like the other significant winter storm cases, featured 500 hPa heights of 3 standard deviations from climatology at 00Z and 12Z on January 26. Then deepened to 504 hPa which was 3.5 standard deviations below normal by 00Z on January 27. This was a storm that set low barometer records over parts of the Ohio Valley, which should give the forecast a reference point as to how infrequent a storm of this magnitude occurs.  At 850 hPa, strong baroclinicity was noted.