Given that this report has to last two weeks it is difficult to be precise in terms of actual HF conditions. What we can say is that we are in turbulent times, with the solar flux index going up and down, and geomagnetic conditions subject to fluctuations as coronal holes and coronal mass ejections come and go.
The NOAA forecast for the next two weeks is that the solar flux index may reduce as we go past Christmas, initially to the 90s and ultimately to the 80s as we head towards the 28th December. NOAA also predicts we may have unsettled geomagnetic conditions on or around the 28th December, possible due to the return of a coronal hole and its associated high-speed solar wind stream. This is very much a guesstimate as this recent crop of sunspots arrived with very little warning. In other words, anything could happen over the next two weeks. At the time of writing there were two active regions on the Sun about to turn to be Earth-facing on the STEREO Ahead spacecraft imagery, but we will have to wait and see how they develop.
What we do know is that mid-Winter is the best time for low-band propagation, so keep an eye on Top Band, 80 metres and 40 metres, which can all show signs of DX activity from afternoon onwards at this time of year. Meanwhile, the higher bands have come into their own with the SFI above 100. If it continues, do check on 12 and 10 metres as they can provide the lowest D-layer absorption and best DX, with some real surprises every now and again. For example, 10m has given quite a few contacts into Australia recently. And 12m has shown good conditions into the mid-west of the USA in the late afternoon before sunset.
So until our regular bulletins start again in the New Year, have a very merry Christmas, a happy New Year and good DX.
And now the VHF and up propagation news:
The good tropo conditions just lasted until the 23cm UK Activity Contest last Tuesday, then a gradual advance of milder Atlantic air with weather fronts, rain and strong winds set the tone for the rest of the week.
The general thrust of the milder air is limited and a battle between cold air to the north and mild to the south will split the country in two over the Christmas weekend. There will be snow in some places for Santa and probably not a lot of VHF propagation to distract him! As a long shot, it can sometimes be productive to beam parallel to a weather front, in this case East to West.
In the week between Christmas and New Year there will be a period of calmer conditions with frosts and a weak ridge of high pressure; so a possible tropo window before the whole pattern returns to mild Atlantic unsettled conditions, but probably with snow on the leading edge.
Finally, to restate last week’s mention; this time of the year can produce surprising out of season Sporadic-E and, with some strong winter jet stream activity, it’s worth a look. Favoured options are to Spain on Boxing Day and more generally to the south and southeast in the second half of the week towards the end of the month. Of course, there’s always a chance of aurora and meteor scatter to keep you amused if the Sporadic-E doesn’t materialise.
The Quadrantid meteor shower peaks overnight from the 2nd of January to the 3rd and can produce a ZHR of 50-100 with some big fireballs. The peak of activity is extremely narrow, lasting only a few hours.
The Moon still has positive declination until the day after Boxing Day and perigee is on New Year’s day, bringing lowest path losses. This day also has high 144MHz sky noise so EME is a bit swings and roundabouts through the holiday period. (sgb.org)
