After the solar chaos of last weekend, things looked a little more settled
at first. However, following last Sunday’s X8.2 solar flare, material from a
coronal mass ejection impacted the Earth on Wednesday. The Solar Flux Index
declined to 75 by Thursday, but we were seeing the geomagnetic effects of yet
another coronal hole as this report was being written.
All this activity
makes it hard to be precise about conditions next week, but NOAApredicts the
solar flux index will be in the mid-80s, with unsettled geomagnetic conditions
at times. Look for a low K-index over a couple of days for the best results on
HF.
It is worth pointing
out that a better indicator of real-time HF conditions can be the smoothed or
averaged smoothed sunspot number, which is currently 17 or 22 according to which
method is used. Smoothed numbers are used by VOACAP and G4FKH’s
own predtest.uk prediction tool.
Propagation Studies
Committee member Marcus, G0IJZ, reminds us that sunspot numbers and solar flux
levels can be chaotic in the short term, but over the long term—that is,
months—there is good correlation between the smoothed indices and ionospheric
characteristics.
As we move into
autumn, this can also be a good time to look for openings on the lower bands.
Quite a lot of DX has been reported on 40m, especially around greyline times.
The band is definitely worth checking.
VHF and up:
Early last week we
saw more of the predicted auroral propagation in the UK, so keep a check on the
lower VHF bands in case the sun flares up again.
After a windswept
and showery last week, there are signs that we start this weekend with the
legacy of cool northwesterly winds and scattered showers, possibly thundery.
This means continuing good rain scatter on the GHz bands from any of the heavier
showers.
Last week, the
weather models were hinting at high pressure building by this weekend, but it
has been knocked back to early in the coming week. It’s still on the agenda for
the southern half of the country and possibly the north at times.
By the end of the
week, there should be a large high near southwest Britain. This could bring
tropo into play for many areas by the time we get past mid-week and it looks
good into the following weekend.
There are no meteor
showers this week, so continue to look before dawn for the best random meteor
scatter contacts.
