Sunspot group 2699 threw a surprise last week when it unleashed a C-class solar
flare and a coronal mass ejection. While we have got used to having coronal hole
activity, CMEs have been less prevalent over the last few months. The CME and a
coronal hole solar wind stream were predicted to reach Earth by Thursday, 15
February. NOAA said the combined effects could generate minor, G1 class storming
at higher latitudes, with a chance for isolated G2 storming as well, and issued
an aurora alert for high latitudes.
The ACE spacecraft showed an increase in
both solar wind density and speed from about 8am on Thursday, but ionospheric
effects appeared minimal. But the full effects were seen later on Thursday
evening when the K-index rose to four.
NOAA predicts that next week the
solar flux index will fall back to around 70, due to a lack of new sunspots.
Geomagnetic conditions may be unsettled at the beginning of the week due to the
ongoing effects of the CME, but should be more settled later in the week. The
maximum usable band over a 3,000km path still tends to be 17 metres, with
occasional openings on 15 metres and higher.
Daytime critical frequencies
are still around 5MHz, so 40 metres is still mostly closed to the UK during the
day. Night time critical frequencies are mostly in the range 2-3MHz, so again 80
metres closes to UK contacts after dark.
VHF and up:
The return of
high pressure means that tropo will play a part this week. Conditions should be
good across the southern half of Britain and well into the continent at times.
Models show some hint that more disturbed weather could bring it to a close
later next week.
There is some talk of a sudden stratospheric warming,
which changes the stratospheric flow to look more like a summer pattern. There
is a thought that this can lead to out of season sporadic E, and therefore well
worth checking the clusters for activity on 28 and 50MHz.
You can keep an eye
on digimodes activity on 50 and 144MHz by monitoring the operational frequencies
for the different digital modes. Just use Google or look at posts on dxmaps.com
to find these frequencies. This can act as a good real time guide for
propagation, but remember to call CQ on the bands even if it seems quiet. If you
don’t transmit, you won’t work the DX!
Moon declination goes positive
this Monday and path losses will fall all week, as the Moon comes closer. This
will give steadily improving EME conditions as the week progresses.
