Routine Space Environment Product (Daily)
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000
FXXX12 KWNP 260031
DAYDIS

:Product: Forecast Discussion
:Issued: 2015 Apr 26 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

Solar activity was low this period. A long duration C1 flare was
observed at 25/1849 UTC that was likely associated with a bright surge
on the limb (BSL) near N11 with a max extent of 0.15 solar radii as
noted by a USAF optical observatory. SOHO/LASCO imagery was just
becoming available at the time of this report and early analysis shows
an associated coronal mass ejection (CME) first visible ejecting off the
northwest limb at 25/1836 UTC that appears to be too far west to be
geoeffective.

Region 2331 (S09W47, Dai/beta-gamma) exhibited consolidation in its
intermediate and leader spot areas while the remaining four active
regions on the visible disk were generally stable.

An asymmetric full-halo CME was observed in SOHO/LASCO C2 imagery
beginning at 25/1448 UTC however, the lack of activity on the visible
disk in any other observed imagery indicated this event was likely
far-sided only.

Two disappearing filaments were observed in GONG H-Alpha imagery earlier
in the period. The first, a 21 degree long filament centered near
S22E19, disappeared between 25/0209-0359 UTC. The second, a 12 degree
long filament centered near S20W32, disappeared between 25/0359-0557
UTC. Both disappearing filaments were non-eruptive and appeared to have
been reabsorbed. No Earth-directed CMEs were observed this period.

.Forecast...
Solar activity is expected to be low with a slight chance for M-class
(R1-Minor) flares over the next three days (26-28 Apr).


Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at
moderate to high levels and reached a peak flux value of 1,310 pfu at
25/1530 UTC. The greater than 10 MeV proton flux at geosynchronous orbit
was slightly enhanced this period but remained below the S1 (Minor)
event threshold.

.Forecast...
The greater than 2 MeV electron flux at geosynchronous orbit is expected
to be at normal to moderate levels with a chance for high levels over
the next three days (26-28 Apr). The greater than 10 MeV proton flux at
geosynchronous orbit is likely to remain enhanced through day one (26
Apr) but is expected to remain below the S1 (Minor) event threshold.


Solar Wind

.24 hr Summary...
Solar wind parameters were at background levels this period. Solar wind
velocity decreased from initial values near 385 km/s to end-of-period
values near 310 km/s. IMF total field strength values varied between
2 nT to 4 nT and Bz remained mostly positive throughout the period. The
phi angle was steady in a positive (away from the Sun) solar sector
orientation.

.Forecast...
Solar wind velocity is expected to remain near background levels over
the next three days (26-28 Apr). Slightly disturbed conditions are
possible during the period due to various solar sector changes before
settling into a positive orientation once again late on day three (28
Apr).


Geospace

.24 hr Summary...
The geomagnetic field was quiet throughout the period under a nominal
solar wind regime.

.Forecast...
Quiet to unsettled field conditions are expected throughout the period
due to various solar sector boundary changes.



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