Solar activity was very low to low. Only low-level C-class activity
was observed from Regions 4384 and 4389. Slight growth was observed
in Regions 4384 and 4391. New Region 4392 was numbered. The rest of
the spot groups were either stable or in decay. No Earth-directed
CMEs were observed. Solar activity is expected to be at low levels,
with a slight chance for M-class (R1-R2/minor-moderate) flares,
through March 14.
Solar wind parameters were enhanced through March 11. Solar wind
speed ranged from approximately 480 to 570 km/s during this time but
decreased to around 400-460 km/s through the rest of the period.
High Speed Stream activity persists through March 14.
Elevated probabilities are related to the flare potential of both
currently observed spot groups as well as the potential from
returning regions.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels March 16 to 19, and then on March 23
to 30 due to the influence from multiple, recurrent, Coronal Hole
High Speed Streams. The remainder of the outlook period is likely to
be at normal to moderate levels.
Geomagnetic field activity is expected to reach G1 (Minor)
geomagnetic storm levels on March 14, 22, and 25 during the onset of
a CH HSS. G2 (Moderate) geomagnetic storm levels are likely on March
21 due to negative polarity CH HSS effects. Unsettled to active
levels are likely on March 15 to 20, 23 and 24, and on March 256 to
28. All elevated levels of geomagnetic activity are associated with
the anticipated influence of multiple, recurrent, CH HSSs. The
remainder of the outlook period is likely to be at mostly quiet
levels.
The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, .
The Predicted Planetary A Index for March 14 to 20 is 20, 15, 10,
10, 10, 12, and 15, with a mean of 13.1. The Predicted Planetary K
Index is 5, 4, 3, 3, 3, 4, and 4, with a mean of 4.1. 10.7
centimeter flux is 110, 110, 110, 110, 110, 105, and 110, with a
mean of 109.3.
For more information concerning shortwave radio propagation, see
and the ARRL Technical Information
Service web page at, For
an explanation of numbers used in this bulletin, see
. Information and
tutorials on propagation can be found at, .
Also, check this:
https://bit.ly/3Rc8Njt
“Understanding Solar Indices” from September 2002 QST.
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