[600MRG] Big Solar Flare

[Paul Signorelli]

18 MHz now open to Caribbean, HI and KP4's, Lots of QSB. 0100z, 5 Sept, 2017.

SA on 21 MHz.

Flux up to 183! Paul   w0rw

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Paul  NA5N has this message for us:

Our quiet sun woke up with an M1 flare smack in the middle of the sun
earlier today (Monday), and what appears to be an M5-M6 flare not long ago
from the same region.  These two flares have sent strong ionizing radiation
to planet earth, ionizing the D, E and F layers.  D-layer ionization is
causing strong HF signal attenuation across North America, and near
blackout conditions from the mid-west to the west coast with maximum
attenuation centered about over Hawaii.  This will persist the rest of
daylight hours.  I only hear two very weak stations on 20M.

Also of interest is the M1 flare produced a Type II storm with the sonic
shockwave measured at around 1400-1500 km/sec.  The M6 flare likely
produced the same shockwave velocity, if not higher.  With the flare site
smack in the center of the sun, this means the CME shock wave will almost
assuredly hit the earth in about three days.  Usually a shockwave leaving
the sun at around 1,000 km/sec. or more will trigger a major geomagnetic
storm with a direct or near-direct hit (which this will likely be).


FORECAST: Expect fairly lousy conditions the rest of the day - daylight
hours.  The D-layer absorption will disappear around sundown, so 40M should
be about normal tonight.  This indicates very good grayline propagation
could exist around sundown as the E and F layers remain ionized as the D-
layer is disappearing.  Try it!  If the X-ray emission from the sun remains
somewhat high, as it is now, the next two days could bring good HF
conditions and long skips awaiting the geomagnetic storm.

Then late Wednesday through early Thursday, expect the onset of a strong or
major geomagnetic storm from the 1400 km/sec shockwave.  Due to two
shockwaves from two M-class flares, the geomagnetic storm will likely
persist for many hours, a good portion of the day.  If the shockwave hits
around midnight, aurora could be seen in the northern tier of states.  Once
the geomagnetic storm subsides, HF conditions are usually very good and
unusually quiet for a couple of days.

NOAA has not yet released the data on the M6 and associated shock wave
yet.  I'll update this if needed when they issue their solar activity
report or issue a geomagnetic storm warning different from the above.

While the above indicates periods of poor HF conditions, it also indicates
the windows between nasty events where QRP can be very effective.

72, Paul NA5N