= NOW 18 WPM transition file follows =

Solar activity reached moderate levels due to an isolated M1.5/1n
flare on March 19 at 2040 UTC from Region AR4031.  Regions AR4028,
AR4034, and AR4035 exhibited slight growth.  Region AR4026 re
emerged in the Southwest quadrant. Regions in the Northwest
quadrant, including AR4020, AR4022, AR4025, and AR4031 all appeared
to be in a decay phase.  No Earth directed CMEs were detected in
available coronagraph imagery.  No S1, Minor, or greater solar
radiation storms are expected through March 23.  No significant
active region activity favorable for radiation storm production is
forecast.  C class flares are expected to continue to March 22, with
a chance for isolated M class, or R1/Minor, flares.  A chance for R1
to R2, or Minor to Moderate, radio blackouts due to M class flares
will persist through March 23.  Weekly Commentary on the Sun, the
Magnetosphere, and the Earths Ionosphere, March 20, 2025, by F. K.
Janda, OK1HH, While the current solar activity is a bit lower than
we would like and then would be consistent with the current phase of
the solar cycle, it may be a prelude to another peak within the
current 11 year cycle maximum.  This hypothesis is supported by the
starting shift of the sunspot activity from the southern hemisphere
of the Sun to the northern hemisphere, see also the M class flares
in AR4031 and the following filament flare, i.e., in the northwest
quadrant of the solar disc.  At the same time, the presently
forecasted period is likely to begin with a transient decrease in
geomagnetic activity. But this may be interrupted as early as March
23 if an enhanced solar wind blowing from Solar Coronal Hole 24 hits
Earth.  If this happens in the daytime, a so called positive phase
of the disturbance could follow with an increase in MUF and a
general improvement in ionospheric shortwave propagation conditions.
Spaceweather.com has a link to an article that discusses new
evidence that cosmic rays spark lightning.  Weak disturbances in the
solar wind are anticipated through March 20 in response to
persistent transient/High Speed Stream, or HSS, effects as well as
possible flanking influences of a nearby CME passage that departed
the Sun on March 17. Solar wind parameters are expected to slowly
diminish on March 21.  Another enhancement is expected late on March
22 due to the arrival of a CIR preceding a negative polarity Coronal
Hole HSS.  A CIR, or Corotating Interaction Region, is a recurring
plasma structure in the heliosphere formed when fast solar wind
streams interact with slower solar wind ahead of them.  Quiet to
unsettled levels are expected on March 21. By late on March 22,
unsettled to active levels are likely due to the aforementioned CIR
arrival.  The Predicted 10.7 centimeter flux for March 21 to 27 is
195, 200, 195, 190, 180, 165, and 160, with a mean of for a mean of
183.6  The Predicted Planetary A Index is 8, 5, 5, 5, 15, 25, and
25, with a mean of 12.6.  The Predicted Planetary K Index is 3, 2,
2, 2, 4, 5, and 5, with a mean of 3.3.

= END OF 18 WPM transition file <