National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXXX12 KWNP 120030
DAYDIS

:Product: Forecast Discussion
:Issued: 2013 Dec 12 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 low. The largest event of the period was a C2 flare
from Region 1917 (S15E17) at 11/2306 UTC. Minor changes were noted in
Region 1917 during the period. Regions 1916 (S12W78) and 1922 (N10W32)
maintained their beta-gamma magnetic structures. The other eight
numbered sunspot groups were either stable or in slight decay. There
were no Earth-directed coronal mass ejections (CMEs) observed in
satellite imagery during the reporting period.

.Forecast...
Solar activity is expected to be low with a chance for M-class flares on
days one, two, and three (12-14 Dec).

Energetic Particles

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels, reaching a peak of 126 pfu at 11/1525 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 be at normal to moderate levels for days one, two, and three (12-14
Dec). The greater than 10 MeV proton flux at geosynchronous orbit is
expected to remain at background levels (below S1-Minor) for the
forecast period (12-14 Dec).

Solar Wind

.24 hr Summary...
Solar wind, as measured by the ACE spacecraft, was indicative of
background conditions. Wind speed reached a peak of 387 km/s at 11/0050
UTC. The total interplanetary magnetic field reached a maximum value of
+4 nT while the Bz component did not drop lower than -2 nT. Phi angle
was oriented in a predominately positive (away) solar sector but showed
signs of negative (toward) sector influence throughout the period.

.Forecast...
Solar wind speed is expected to remain at background levels on day one
(12 Dec). Day two (13 Dec), should see the onset of a negative-polarity
coronal hole high-speed stream (CH HSS) in which solar wind parameters
are expected to show an increase in velocity, temperature, and density,
with density gradually decreasing. A solar sector boundary change to a
negative (toward) orientation is anticipated prior to the CH HSS
arrival.

Geospace

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

.Forecast...
The geomagnetic field is expected to be at quiet levels on day one (12
Dec) and the first half of day two (13 Dec). Unsettled to minor storm
levels are expected late on day two in conjunction with the arrival of a
corotating interactive region followed by a CH HSS. Day three (14 Dec)
is expected to be unsettled to active as CH HSS effects continue.