This past week was more settled geomagnetically with the K-index generally
staying around zero or one. This was thanks to a lack of solar coronal hole
activity and the associated high-speed solar wind streams. The solar flux index
declined from the high to mid 90s as large sunspot 2546 rotated out of view.
This has left a rather sparse-looking solar disk with only one sunspot group
visible. As a result the solar flux index is predicted to remain around 90 in
the coming week. NOAA predicts the geomagnetic K-index rising again to an
unsettled four on Monday and Tuesday.
Looking further ahead it
doesn’t look good for next weekend’s HF CW National Field Day as plasma from a
recurring solar coronal hole could push the K-index up to five. This could see
the HF bands become noisy and maximum usable frequencies fall away.
Apart from occasional
short-skip sporadic-E openings on 10 and 15m, the highest ‘money’ band for Field
Day is predicted to be 20m, with 15m perhaps struggling to open to DX. Forty
metres may give consistent openings around Europe, with DX being workable at
night. Eighty metres may give good openings around Europe after dark, but is
unlikely to yield much DX.
VHF and up propagation
news:
Next week sees high pressure
between Iceland and Scotland with low pressure over the near continent. This
will mean a north-easterly flow of air from the North Sea. In the summer months,
this can lead to extensive mist and sea fog along eastern coasts and give some
good tropo conditions from East Anglia to Aberdeen and Lerwick.
This type of tropo depends upon
warm moist air blowing off the continent and out across the cool North Sea to
give longer DX paths to Denmark, for example. However, with a north-easterly
wind it usually means dry cool air gets folded into the mix, and I suspect we
may be limited to paths up and down the east coast.
Last week saw some excellent
sporadic-E openings on six and four metres. Conditions on Wednesday extended
from Scandinavia round to the Balkans and central Mediterranean.
For next week it’s not a good
sign that there seem to be few suitably-placed jet streams, often involved with
sporadic-E formation. They are mostly located over Spain and the Mediterranean
and so a bit too far away.
EME conditions will improve
next week with increasing declination and the moon at perigee on Friday.