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FXXX12 KWNP 210031

:Product: Forecast Discussion
:Issued: 2014 Dec 21 0030 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
#             Forecast Discussion
Solar Activity

.24 hr Summary...
Solar activity began the period at high levels as Region 2242
(S19W44, Fkc/beta-gamma-delta) produced an X1/3b flare at 20/0028 UTC.
Associated with this event was a Type II radio sweep (est. speed 900
km/s), a 2300 sfu Tenflare, and a coronal mass ejection (CME) directed
off the SW limb. Analysis of SOHO/LASCO coronagraph imagery indicated
the majority of the ejecta was not Earth-directed, heading well south of
the Sun/Earth plane. Region 2242 exhibited signs of separation and decay
in the intermediate spot area while continuing to maintain a delta
magnetic configuration.

The second largest spot group on the visible disk, Region 2241 (S11W21,
Ekc/beta-gamma-delta), was relatively stable and quiet over the period,
despite the presence of delta within its trailing spots. No significant
flaring was observed from this region during the period.

Solar activity is expected to be at moderate (R1-R2/Minor-Moderate)
levels with a chance for further X-class flaring (R3-Strong or greater)
for the next three days (21-23 Dec) as Regions 2241 and 2242 remain
large and magnetically complex.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels. The greater than 10 MeV proton flux was at
background levels.

The greater than 2 MeV electron flux is expected to be at normal to
moderate levels for the forecast period (21-23 Dec). There is a chance
for a greater than 10 MeV proton event (S1-Minor) due to the potential
for significant flare activity from Regions 2241 or 2242.

Solar Wind

.24 hr Summary...
Solar wind parameters continued at nominal levels throughout the period.
Solar wind speeds ranged from 318 km/s to 406 km/s. The total field
remained relatively steady near 6 nT, while the Bz component was
variable between +/- 6 nT. Phi angle was oriented in a positive (away)

Solar wind parameters are expected to become enhanced on day one (21
Dec) as the first of two CMEs is expected to impact the geomagnetic
field. This CME is not likely to have significant impacts at Earth as it
is expected to only be a glancing blow from the 17 Dec CME. A second
CME, this one from 18 Dec, is expected by midday on day one. Solar wind
speeds reaching the 650-750 km/s range are estimated with the arrival of
this CME. A disturbed solar wind environment is expected to continue
into day two (22 Dec) as CME effects linger.


.24 hr Summary...
The geomagnetic field was quiet.

The geomagnetic field is expected to continue at mostly quiet
conditions through the beginning of day one (21 Dec), when a glancing
blow from the 17 Dec CME is expected to become geoeffective.
Unsettled to active periods with a chance for minor storm periods
(G1-Minor) is expected to dominate late on day one, lasting into day two
(22 Dec). This storm could also cause minor to major storming (G1-G2,
Minor-Moderate) as it impacts the Earths magnetosphere. Unsettled to
active periods are expected to persist through the majority of day three
23 Dec). is the U.S. government's official web portal to all federal, state and local government web resources and services.