[Propagation+Space Weather] Today's Space Weather Forecast Discussion on 2015 May 09 1230 UTC

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Here is the current forecast discussion on space weather and geophysical activity, issued 2015 May 09 1230 UTC.

Solar Activity

24 hr Summary: Solar activity was low. Region 2339 (N12E30, Fkc/beta-gamma) produced an impulsive C5/1n flare at 08/0409 UTC and an impulsive C4/Sf flare at 08/0940 UTC. Region 2339 continued to be the largest and most complex region on the visible disc. The region remained relatively stable and showed little change during the period. Region 2335 (S16W36, Csi/beta) continued to slowly and gradually decay. The remaining regions on the visible disk were either stable or in decay.

A long duration C7/Sf flare occurred at 09/0134 UTC from a region just behind the east limb at approximately N17. The flare spawned an impressive EPL, reported by USAF optical observations and observed in SDO/AIA 304 imagery. In addition, during 09/0003 to 0150 UTC, an approximately 26 degree long filament erupted in the NE quadrant. The filament, centered near N35E38, erupted to the north and west of Region 2339. Analysis of SDO/AIA and GONG H-alpha imagery indicated the western portion of the filament was likely reabsorbed while the eastern portion appeared to have lifted off. SOHO/LASCO C2 and C3 imagery observed a coronal mass ejection (CME) off the NE limb, likely a result of the events described above. Initial analysis, and subsequent WSA-Enlil model output, indicated a clear miss to the north and east of Earth. Further analysis continues as more data becomes available. No additional CMEs were observed this period.

Forecast: Solar activity is likely to be moderate (R1-R2/Minor-Moderate) with a slight chance for X-class (R3 or greater) flares over the next three days (09-11 May).

Energetic Particle

24 hr Summary The greater than 2 MeV electron flux was at normal levels and the greater than 10 MeV proton flux remained at background levels throughout the period.

Forecast: The greater than 2 MeV electron flux is expected to be at normal to moderate levels on days one and two (09-10 May) and at normal levels on day three (11 May) as a negative polarity coronal hole high speed stream (CH HSS) becomes geoeffective. The greater than 10 MeV proton flux is expected to persist at background levels over the next three days (09-11 May).

Solar Wind

24 hr Summary: Solar field parameters, as measured by the ACE satellite, were indicative of an ambient solar wind environment during the period. Solar wind velocity varied between 362 to 433 km/s. IMF total field values were steady at about 6 nT until 09/0630 UTC when Bt field strength varied between 3-8 nT. Bz reached a maximum southward deflection of -3 nT late in the period. The phi angle was steady in a negative (toward) solar sector configuration throughout the period. A subtle rise and sudden drop in magnetic field strength from 09/0630-0900 UTC, accompanied by a rise in density and wind speed, may have indicated a weak transient feature that had no associated geomagnetic field response at Earth.

Forecast: Solar wind parameters are expected to remain at background levels on days one and two (09-10 May) under a nominal solar wind regime. A solar wind enhancement is expected late on day three (11 May) due to the onset of a co-rotating interaction region (CIR) out ahead of a negative polarity CH HSS.

Geospace

24 hr Summary: The geomagnetic field was quiet this period under a nominal solar wind regime.

Forecast: The geomagnetic field is expected to continue at quiet levels on days one and two (09-10 May) under an ambient solar wind environment. Quiet to unsettled levels are expected for the majority of day three (11 May). By late on day three, the onset of a CIR preceding a negative polarity CH HSS is likely to cause periods of active geomagnetic activity.

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