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FXXX12 KWNP 051231

:Product: Forecast Discussion
:Issued: 2016 Dec 05 1230 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 reached low levels this period due to C-class flare
activity. Region 2615 (S07W27, Dai/beta) produced a pair of C1/Sf flares
this at 04/1755 UTC and 05/0607 UTC. The region exhibited minor growth
in its trailer and intermediate spot areas. Region 2612 (N09W82,
Hax/alpha) was stable throughout the period.

Other activity included an eight degree long filament eruption centered
near N12W42. At about 04/1330 UTC, SDO/AIA 304 and GONG imagery observed
a filament eruption just to the south of Region 2616 (N18W54) which
decayed to plage 24 hours earlier. LASCO C2 imagery observed a CME off
the NW limb, first visible at 04/1412 UTC. Analysis, and subsequent
WSA-Enlil model output, suggested the CMEs trajectory was well west of
the Earth-Sun line and not expected to impact Earth. No other CMEs were
observed in available coronagraph imagery.

There is a chance for C-class flares and a slight chance for M-class
flare activity over the next three days (05-07 Dec).

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux reached high levels this period
with a peak flux of 6,344 pfu observed at 04/1605 UTC. The greater than
10 MeV proton flux was steady at background levels.

The greater than 2 MeV electron flux is expected to reach high levels on
days one and two (05-06 Dec) with normal to moderate levels likely on
day three (07 Dec) due to elevated geomagnetic field activity. The
greater than 10 MeV proton flux is expected to persist at background
levels throughout the forecast period.

Solar Wind

.24 hr Summary...
Solar wind parameters became slightly enhanced beginning at around
04/1300 UTC, likely due to a solar sector boundary crossing. Bt and Bz
were at background levels until around 04/1400 UTC when Bt increased to
4 nT and Bz reached -4 nT following a phi angle transition (negative to
positive) at 1100 UTC. Solar wind density values also became enhanced
following the sector change, but solar wind speeds remained steady
between 270-280 km/s.

At about 05/0215 UTC, the phi angle switched back from a positive to a
negative orientation. An increase to 8 nT in Bt was observed with a
decrease in density values. Wind speeds slowly increased through the
remainder of the period from near 280 km/s to about 310 km/s.

The near-Earth solar wind environment is expected to be slightly
enhanced on day one (05 Dec) due to the weak influence of a positive
polarity CH HSS. Background solar wind conditions are expected on day
two (06 Dec) followed by another solar wind enhancement beginning on day
three (07 Dec) due to the anticipated onset of a recurrent negative
polarity CH HSS. STEREO-A data suggests that wind speeds in excess of
700 km/s are possible during the onset of this feature.


.24 hr Summary...
The geomagnetic field was at quiet levels throughout the period.

The geomagnetic field is expected to be quiet to unsettled on day one
(05 Dec) due to the influence of a positive polarity CH HSS. Quiet
conditions are expected on day two (06 Dec) followed by likely quiet to
active conditions on day three (07 Dec) due to the onset of a negative
polarity CH HSS. is the U.S. government's official web portal to all federal, state and local government web resources and services.