[Propagation+Space Weather] Today's Space Weather Forecast Discussion on 2015 May 14 1230 UTC

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Here is the current forecast discussion on space weather and geophysical activity, issued 2015 May 14 1230 UTC.

Solar Activity

24 hr Summary: Solar activity remained at low levels. Two filament eruptions were noted during the period. The first occurred south of Region 2341 (S20W12, Hsx/alpha) around 13/1612 UTC. A Sf flare from Region 2341 followed at 13/1630 UTC. A Type II radio sweep and a Type IV radio burst were reported at 13/1634 UTC and either associated with this filament eruption or a prominence eruption from the southwest limb around the same time. This filament eruption was accompanied by a CME first visible in SOHO/LASCO C2 coronagraph imagery emerging from the southeast limb at 1712 UTC. The ejecta appeared to be directed south and east of the Earth-Sun line and was relatively narrow. No modeling of this event has been attempted.

The second filament eruption occurred near N16W16 was associated with the largest flare of the period, a C9/1N event at 13/1838 UTC. A Type II radio sweep (est. shock speed 1568 km/s) was also reported by Sagamore Hill observatory at 13/1821 UTC. SOHO/LASCO C2 coronagraph imagery showed an asymmetric halo CME emerging at 13/1828 UTC. Plane of sky speed was estimated at 300-450 km/s. The bulk of the ejecta appeared to be moving northward. Two WSA-Enlil model solutions were obtained for this event. The first encompassed the entire shock and suggested an arrival on 16 May around 0700 UTC. The second focused solely on the bright ejecta to the north and suggested a modest glancing blow on 17 May around 0300 UTC. At this point, the second solution seems most reasonable, but further analysis will be accomplished.

Region 2339 (N11W38, Fkc/beta-gamma) remained the most complex region on the disk but only managed to produce a C2 flare at 0731 UTC. Decay of the leading and intermediate spots of this region was balanced by some flux emergence in the trailer spots. Intermediate spot growth was noted in Regions 2342 (N17E01, Cao/beta) and 2346 (S08E35, Cao/beta). New Region 2348 (S10E65, Hsx/alpha) was numbered. New flux was emerging near N19W06 and is being monitored. Finally, the unnumbered spot group near N12E52 appeared to decay.

Forecast: Solar activity is expected to be low with a chance for M-class (R1-R2/Minor-Moderate) flare activity over the next three days (14-16 May) with Region 2339 being the most likely source.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux at geosynchronous orbit reached high levels (1000 pfu) at 14/0920 UTC. The greater than 10 MeV proton flux at geosynchronous orbit was at background levels.

Forecast: The greater than 2 MeV electron flux at geosynchronous orbit is expected to persist at moderate to high levels in response to the high speed solar wind stream described below. The 10 MeV proton flux is expected to remain below S1 (Minor) thresholds.

Solar Wind

24 hr Summary: The high speed stream dominated the solar wind environment at the ACE spacecraft. Wind speed was in the mid-600 to mid-700 km/s range; phi was negative, Bt was at or below 6 nt and Bz was at or above about -5 nT. The total magnetic field magnitude generally decreased through the period.

Forecast: The solar wind environment at the ACE spacecraft is expected to continue to reflect the high speed stream over the next three days (14-16). This may be complicated by CME passage on 16 May.

Geospace

24 hr Summary: The geomagnetic field was at quiet to active levels.

Forecast: The geomagnetic field is expected to be at unsettled to active levels, with a diminishing chance of a minor storm. Days two through three (15 - 16 May), are expected to see a gradual slackening of the solar wind and a return to predominantly quiet to unsettled conditions. This trend could be disrupted should the CME described above pass on the 16th. At this point, only active levels are anticipated should this occur.

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