Routine Space Environment Product (Daily)
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000
FXXX12 KWNP 211231
DAYDIS

:Product: Forecast Discussion
:Issued: 2015 Apr 21 1230 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 reached moderate (R1-Minor) levels as Region 2322
(N11W80, Dac/beta) produced an impulsive M1/Sf (R1-Minor) flare at
21/0721 UTC. A region just beyond the East limb then produced an M2/Sf
flare at 21/1040 UTC. Another M-class flare was in progress at the time
of this summary. Magnitude and location will be determined as imagery
becomes available. Representative LASCO coronagraph imagery is not
yet available to determine if there were associated CMEs from the
M-flares.

Regions 2321 (N07W51, Hsx/alpha), 2322, and 2324 (N19W26, Cai/beta) also
produced low level C-class flares during the period. New regions 2331
(S10E17, Bxi/beta) and 2332 (S13W10, Bxo/beta) were numbered today, but
were relatively inactive throughout the period. The four remaining
numbered regions on the visible disk were mostly inactive.

The coronal mass ejection (CME) first observed in LASCO C2 imagery at
21/0312 UTC appeared to be from an area just beyond the East limb and
should pose no threat to Earth. No Earth-directed CMEs were observed
this period.

.Forecast...
Solar activity is likely to be low with a slight chance for M-class
(R1-Minor) flares over the next three days (21-23 Apr) as Region 2322
rotates off the visible disk and the active region just beyond the East
limb rotates on.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at normal to high levels this
period, reaching a peak of 2620 pfu at 20/1905 UTC. The greater than 10
MeV proton flux was at background levels throughout the period.

.Forecast...
The greater than 2 MeV electron flux is expected to be at moderate to
high levels over the next three days (21-23 Apr) in response to the
anticipated onset of a positive polarity coronal hole high speed stream
(CH HSS). The greater than 10 MeV proton flux is expected to persist at
background levels over the next three days (21-23 Apr).

Solar Wind

.24 hr Summary...
Solar wind parameters reflected an ambient solar wind regime for the
first half of the period. Solar wind velocities were steady near 390
km/s, IMF total field values were steady between 4-6 nT while Bz reached
a maximum southward component of -7 nT. After approximately 21/0215 UTC,
velocities increased to just over 600 km/s, total field was near 9 nT,
and Bz became variable between -7 nT and 9 nT. Phi angle had switched
from negative (towards) to a positive (away) orientation right at the
beginning of the period and remained mostly positive throughout the
remainder of the period. This increase in activity is likely the onset
of the anticipated positive polarity coronal hole high speed stream (CH
HSS)

.Forecast...
Solar wind parameters are expected to become further enhanced late on
day one (21 Apr) due to the anticipated arrival of the 18 Apr CME, as
well as the influence of the CH HSS. Elevated solar wind velocities and
magnetic tendencies are forecast to persist through day two (22 Apr).
Solar wind parameters are expected to begin decreasing midday on day
three (23 Apr) as CH HSS and CME effects begin to wane.

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 minor (G1-Minor) storming likely for the remainder of day one (21
Apr). The anticipated arrival of the 18 Apr CME midday on day one is
expected to trigger periods of G1 (Minor) geomagnetic storm conditions
in conjunction with the positive polarity CH HSS. Day two (22 Apr) is
forecast to persist with G1 conditions. Unsettled to active conditions
are expected to return after 0900 UTC on day three (23 Apr) as CH HSS
and CME effects subside.


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