[Propagation+Space Weather] Today's Space Weather Forecast Discussion on 2015 Sep 18 1230 UTC

[nw7us@sunspotwatch.com]

This e-mail posting is from the Radio Propagation Reflector that you're 
currently subscribed to.  Refer to the end of this e-mail for directions on how 
to change your subscription options, or to unsubscribe.
_______________________-start-_________________

Here is the current forecast discussion on space weather and geophysical activity, issued 2015 Sep 18 1230 UTC.

Solar Activity

24 hr Summary: Solar active was at low levels. Region 2415 (S19W22, Eac/beta-gamma) produced numerous C-class flares, including a long duration C2/Sf flare that occurred between 18/0631 UTC. Type II (850 km/s) and IV radio sweeps accompanied this event indicating there is a possible CME associated. Further analysis is needed as coronagraph imagery updates to see if there is ejecta with an Earthward component. The region grew in areal coverage and linear extent, while it retained magnetic mixing near the spot groups center. Region 2419 (N13E15, Cao/beta) dissipated slightly and was inactive. Region 2418 (S15E11, Cso/beta) developed a few umbra in the trailing negative polarity field, but remained inactive and stable.

Forecast: Solar activity is expected to be at low levels, with a chance for M-class (R1-R2/Minor-Moderate) flares all three days (18-20 Sep), primarily due to the flare probability of Region 2415.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux ranged from normal to high levels with a peak flux of 6940 pfu at 17/1545 UTC. The greater than 10 MeV proton flux was at background levels.

Forecast: The greater than 2 MeV electron flux is expected to be at moderate to high levels on day one and into day two (18-19 Sep). Electron flux is expected to decrease to normal to moderate levels by day three (20 Sep) due to the onset of a coronal hole high speed stream (CH HSS). The greater than 10 MeV proton flux is expected to continue at background levels.

Solar Wind

24 hr Summary: The solar wind and interplanetary magnetic field (IMF) parameters were indicative of waning positive polarity CH HSS conditions early. Later in the period, a solar sector boundary crossing (SSBC) to a negative orientation was observed. Solar wind velocities were variable between 450-500 km/s early in the period, but slowly decreased after 17/1545 UTC. The IMF total field strength was primarily between 4-7 nT. The Bz component was variable with a maximum southward deflection of -6 nT. The phi angle was in a positive (away from the Sun) sector early, with oscillation into negative with the SSBC beginning near 18/0600 UTC.

Forecast: Solar wind velocities are expected to remain at nominal levels throughout day one (18 Sep). Late on day two (19 Sep) a weak co-rotating interaction region (CIR) may reach Earth ahead of the isolated, positive polarity CH HSS from CH02. Enhanced conditions are expected to continue on day three (20 Sep) due to CH HSS influences.

Geospace

24 hr Summary: Geomagnetic activity was at quiet to unsettled levels.

Forecast: Geomagnetic activity is expected to be quiet to unsettled on day one, continuing through most of day two (18-19 Sep). A weak CIR ahead of the positive polarity CH HSS may arrive as early as late on day two, and could cause a geomagnetic response to active levels. Day three (20 Sep) is expected to reach unsettled to active levels due to CH HSS effects.

Don't forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx

Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!

Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g

We're on Facebook: http://NW7US.us/swhfr

Live data: SunSpotWatch.com

_______________________________________________
Propagation mailing list
Propagation@contesting.com

To change your subscription settings, or to unsubscribe, visit:
http://lists.contesting.com/mailman/listinfo/propagation