A glancing blow from a high-speed solar wind stream caused the K-index to rise
to three on Wednesday. This was a little unexpected as it came from a polar
coronal hole on the Sun that didn’t look like it would impact the Earth. This
brought mixed blessings as an initial positive phase saw the maximum usable
frequency over 3,000km exceed 18MHz. But conditions soon dropped back and 20
metres became the highest viable band for F-layer propagation.
Sporadic
E has been bringing some good short skip to the higher bands so do make the most
of it, with the peaks generally around mid-to-late morning and again in the late
afternoon and early evening.
The good news is we are seeing some sunspot
activity, albeit very weak. At the time of writing there were two small visible
regions and another coming around the sun’s limb. Nevertheless, NOAA predicts
the solar flux will remain around 70.
Geomagnetic conditions are set to
be settled this week, at least until Friday the 1st when NOAA has the K index
rising again. This is due to another coronal hole, which may cause unsettled
conditions over the weekend of the 2nd and 3rd with a maximum predicted K index
of six.
So better HF conditions may occur in the first half of the week,
but the weekend might not be the best time for DX. A high-speed solar wind may
also not be conducive to stable Sporadic E cloud formation either, although this
is an area that needs some more research.
VHF and up:
The next
week carries on in similar fashion with low pressure close to southern Britain,
offering a chance of rain scatter in any showers. The north of the country
remains close to high pressure over Scandinavia with a chance of further patches
of enhanced tropo across the North Sea.
The southern half of the country
will be nearer to low pressure over the continent and will have an enhanced risk
of showers, some thundery. This will make rain scatter a possibility for the
microwave bands.
Sporadic E is amongst us and hopefully this next week
will continue to provide options. However, since jet streams are often
implicated in the formation of sporadic E, the news is not so good in that the
main Atlantic jet stream is displaced well to the north of Europe.
The
main operating rules are to check the clusters and beacons for activity,
initially on 10m, but then upwards through 6m to 4m and 2m as the opening
develops. Conditions may only happen for brief moments, so keep the overs short
with report and locator in case the path fades.
Moon declination is
negative this week, and apogee just a week away so losses are approaching their
highest and moon windows will be at their shortest. This means low antenna
elevations and increasing noise at VHF and UHF.
