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000
FXXX12 KWNP 240031
DAYDIS

:Product: Forecast Discussion
:Issued: 2013 May 24 0030 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity was at low levels.  The largest flares of the period were
a C3/Sf at 23/1450 UTC and another C3 at 23/1847 UTC, both from Region
1756 (S20E27, Ehi/beta-gamma).  Region 1756 had slight growth in the
trailing spots.  Separation and slight decay was observed in the
trailing spots of Region 1755 (N11E40, Dhi/beta-gamma).  The rest of the
spotted regions were relatively stable.  No Earth-directed coronal mass
ejections (CMEs) were observed during the period.

.Forecast...
Solar activity is expected to be low with a chance for M-class flares
and a slight chance for X-class flares for the forecast period (24-26
May).

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux measurements at geosynchronous
orbit were contaminated by the recent proton event and were unreliable
since 22/1420 UTC.  The greater than 10 MeV protons above the 1000 pfu
(S3-Strong) level that began at 23/0330 UTC, reached a maximum of 1660
pfu at 23/0650 UTC, and crossed below the S3 threshold at 23/1040 UTC.
The greater than 100 MeV proton event that began at 22/1455 UTC, reached
a maximum of 3.5 pfu at 22/1830 UTC, and ended at 23/0745 UTC.

.Forecast...
The greater than 2 MeV electron flux at geosynchronous orbit is likely
to have unreliable readings until the greater than 10 MeV proton flux
returns below threshold values.  The greater than 10 MeV proton event is
expected to continue through day 1 (24 May) and likely into the first
half of day 2 (25 May).  There is a chance for a greater than 10 MeV
proton event on day 3 (26 May).

Solar Wind

.24 hr Summary...
Solar wind speed, as measured by the ACE spacecraft, reached a peak
speed of 475 km/s at 23/1933 UTC, however ACE/SWEPAM data were suspect
due to proton contamination from the 22 May M5 flare.  Total magnetic
field ranged from 4 nT to 8 nT while the Bz component was variable
between +6 nT and -5 nT.  Phi angle was negative (towards) through the
period.

.Forecast...
Solar wind speeds are expected to become enhanced by mid to late day 1
(24 May) due to a glancing blow from the 22 May partial halo CME.
Conditions are expected to continue to be enhanced on days 2-3 (25-26
May) due to a combination of continued CME effects followed by a coronal
hole high speed stream (CH HSS).

Geospace

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

.Forecast...
The geomagnetic field is expected to be mostly quiet through the first
half of day 1 (24 May).  By mid to late on day 1, a glancing blow from
the 22 May CME is expected to impact the geomagnetic field causing
active to minor storming levels.  Unsettled to active levels are
expected to persist into day 2 (25 May) as CME effects wane and CH HSS
effects begin.  CH HSS effects are expected on day 3 (26 May) causing
quiet to unsettled levels.