Ten Meters is hot, and seasonally at its annual peak. Good openings to Europe are a daily occurrence, and many CW-phobic newcomers to our hobby are getting their first taste of real DX. Looking at the recent solar numbers, there is still room for improvement. The spike in solar flux to 180 at the end of August gave cause for optimism, but the range for this fall looks more like 120 to 160. We hope for 160 in the contest, though the probability is not good.
The quality of European openings vary widely within this range. At 120, we get most of Europe from Texas - but very little of Russia. With a flux of 160, we get an opening which lasts through the morning and includes all of European Russia. It takes a good broad opening to produce high rates and QSO totals on 10 in a contest. The broadest openings will be from the eastern US, where Russia will come through fine on a flux of 120. The west coast would have a very narrow window in such an event, as the band would close across most of Europe before it even opens out west. The CQWW will not be fair to everyone on 10.
15 is actually in better shape, since the moderate flux levels are not much of a hinderance. Reliable openings occur over high latitude paths, and the band does not close so abruptly at sundown. We can work into Asia and the Pacific after dark, and openings to Europe continue after their local sunset. For the central and western US, this will be the most productive rate band if 10 doesn't play well on contest weekend.
Openings on both bands will be very predictable: day paths. Nighttime MUFs are plummeting; closing 20 Meters in the evening by midnight and moving activity to the low bands. QRN levels are down to where 40 is in excellent shape. 40 SSB has other problems (shortwave QRM), and many SSB ops look to 75 Meters in lowband season for their evening DXing. The European opening on 40 lasts through the evening here, though most activity comes from the sunrise areas where the band is peaking and people are actually up. The other peak to Europe is in the late evening on their end - late afternoon for most of us (and just after dark on the east coast).
20 will be harder to read in the contest. The nightpaths are closed, the daypaths are marginal, and signals propagate best along the grey line. Peak times are several hours before and after sunset, and the hours after sunrise. We work into other areas in the vicinity of the local grey line. The morning opening includes excellent daily long path to the southwest and parts of the world normally hard to reach. Nighttime MUFs are higher in the southern hemisphere, and we can work into and across these nightpaths as long as we are near the greyline ourselves.