[Propagation+Space Weather] Today's Space Weather Forecast Discussion on 2015 Apr 29 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 Apr 29 1230 UTC.

Solar Activity

24 hr Summary: Solar activity was very low; no C-class flares were observed. However, there were several filament eruptions. A 38 degree filament erupted in the NE between 28/1200-1400 UTC and a CME was subsequently observed in SOHO/LASCO C2 imagery beginning at 28/1408 UTC with the ejecta directed eastward. Parametrization and modeling of the CME suggested no significant impacts at Earth. A 14 degree filament located further east erupted between 28/2100-2300 UTC. Finally, a small filament erupted in the northwest between 29/0400-0600 UTC.

Of the several CMEs observed in SOHO/LASCO C2 coronagraph imagery, two candidates may require further analysis. A faint asymmetric partial halo was observed emerging from the north beginning around 29/0000 UTC. Plane of sky estimates suggested it was moving at 320 km/s. Another slow asymmetric partial halo was observed emerging from the east at 29/0248 UTC.

Additionally, brightening in H-alpha and subsequent darkening in SDO/AIA 193 imagery was observed between 28/1945-2121 UTC in the vicinity of Region 2333, although neither a significant X-ray event nor an optical flare was recorded.

There were only two numbered regions on the visible disk by the end of this period. Region 2333 (N21W20, Cro/beta) had decayed over the past 24 hours while Region 2327 (S09W83, Hsx/alpha) was stable. A new flux emerged near S20E37 and is being monitored.

Forecast: Solar activity is likely to be low over the next three days (29 Apr-01 Mar). The lack of significant regions on the disk, or returning, suggests activity may decline further to very low levels.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux at geosynchronous orbit was at low to moderate levels this period. The greater than 10 MeV proton flux at geosynchronous orbit was at background levels throughout the period.

Forecast: The greater than 2 MeV electron flux is expected to be at low to moderate levels over the next three days (29 Apr-01 Mar). The greater than 10 MeV proton flux is expected to persist at background levels throughout the forecast period.

Solar Wind

24 hr Summary: The solar wind environment at the ACE spacecraft was characterized by modest solar wind speeds in the low-to-mid 300 km/s range, although speed did dip to a minimum of 270 km/s between 29/0600-0800 UTC. Phi was variable, but began to approach positive values after 29/0400 UTC. Bt was at or below 8 nT and Bt was at or above -5 nT.

Forecast: Solar wind parameters are expected to remain at background levels for day one (29 Apr). A perturbation is anticipated on day two (30 Apr) ahead of a positive polarity coronal hole high speed stream (CH HSS) that is forecast to persist through the end of the forecast period. The positive hole appears much smaller than during the last rotation, and slightly behind recurrence. Consequently, the forecast may need to be adjusted to account for the differences.

Geospace

24 hr Summary: The geomagnetic field was quiet under the benign solar wind regime.

Forecast: The geomagnetic field is expected to remain at quiet levels on day one (29 Apr). Quiet to unsettled levels become likely on days two and three (30 Apr - 01 Mar) in response to the anticipated onset of the CH HSS.

Further analysis of the coronagraph imagery will be needed before rendering a verdict on the potential geoeffectiveness of the CMEs described above. However, the relatively modest plane of sky speeds suggests any arrival would occur outside this forecast period.

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!

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