This is true that warm October's correlate to warm winters at DFW. However, there is an exception and that is 1947-48. That October was also on the warm side but that winter was very cold (see below). However, I'm starting to worry as well that this will be another blow torch winter. Especially with the Arctic as warm as it has been. If the signals come together for cold to be delivered, but there really isn't much cold to deliver, then it can be all that cold right?
So far we have not fallen, officially at DFW Airport, below 50°F (although I know Arlington and Fort Worth both have). There have only been 4 years where this hasn't happened in October, 1947, 1950, 2004, 2015. 2016 will likely join the ranks as year number five. All of those were warm winters except for 1947-48 (very cold against averages), 1950-51 (slightly cold against averages, although lowest temp was 6°F that winter).
Winter 1947-48 overall was -5.1 below normal
December was -4.4 below normal with the coldest temp of 27°F.
January was -7.5 below normal with 3 distinct snow/ice events with a prolonged Arctic outbreak. The first snow event was on 1/19/48 with 2.0 inches of snow in a WAA pattern form Artic outbreak which began on 1/17/48 with coldest temp of 16°F. The big Arctic outbreak began on 1/24/48 and lasted through 1/30/48 with 6 consecutive days of subfreezing temps. Two snow events culminated in a total of 6.2 inches of snow/ice with lowest temp of 11°F during period and for the month.
February was -3.6 below normal with two major ice storms. One on 2/8/48 0.4 ice followed by low of 19°F. The second over two days 2/12 - 2/13 resulting in 0.5 ice followed by low of 21°F. This look to be more of WAA ice storm. Coldest temp of the month was 19°F.
Winter 1950-51 was -0.3 below normal for winter...
It did have a major Arctic outbreak the end of January into early February 1951 that left 5 days consecutive of subfreezing temps. The lowest temp was 6°F and 8°F on two separate days. There was snow and ice up to 2 inches during this outbreak. Another snow storm of 3.0 inches occurred on 2/14/51 with lowest temp of 21°F.