Routine Space Environment Product (Daily)
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000
FXXX12 KWNP 040030
DAYDIS

:Product: Forecast Discussion
:Issued: 2015 May 04 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 this period.  Region 2335 (S16E37, Dac/beta)
produced multiple C1 flares this period and continued to show signs of
overall growth.  Region 2336 (N13E12, Bxo/beta) decayed this period and
new Regions 2237 (S16E56, Axx/alpha) and 2338 (N04E56, Axx/alpha) were
numbered this period but were otherwise unremarkable.

An asymmetrical partial-halo coronal mass ejection (CME) associated with
yesterdays disappearing solar filament in the southern hemisphere
between 02/1500-1800 UTC was observed in SOHO/LASCO C2 imagery beginning
at 02/2112 UTC.  Subsequent forecaster analysis and WSA-ENLIL model
guidance suggests CME arrival at around 1600 UTC on day three (06 May).

.Forecast...
Solar activity is likely to be low over the next three days (04-06 May)
due to flare activity from Region 2335 and the return of old Region 2322
(N12, L=119) which produced six M-class flares last rotation and was
likely the source of recent back-sided activity indicated by coronagraph
imagery.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at normal to moderate levels
this period, reaching a peak flux value of 194 pfu at 03/1815 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 normal to
moderate levels over the next three days (04-06 May) and 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 were indicative of waning influence of a positive
polarity coronal hole high speed stream (CH HSS).  Solar wind velocity
was steady at around 400 km/s, IMF total field values decreased from 7
nT to 5 nT, and Bz reached a maximum southward component of -5 nT late
in the period.  The phi angle remained in a positive (away from the Sun)
solar sector orientation.

.Forecast...
Solar wind parameters are expected to be at near-background levels on
day one (04 May) and through the majority of day two (05 May) under a
nominal solar wind regime.  A minor solar wind enhancement is likely
late on day two (05 May) through midday on day three (06 May) due to the
onset of a weak negative polarity CH HSS.  A further solar wind
enhancement is anticipated at around 1600 UTC on 06 May due to the
arrival of the 02 May CME.

Geospace

.24 hr Summary...
The geomagnetic field began the period at unsettled levels between
03/0000-0600 UTC due to remnant CH HSS effects but decreased to quiet
levels after 0600 UTC where it remained for the rest of the period as CH
HSS influence subsided.

.Forecast...
The geomagnetic field is expected to be at quiet levels on day one (04
May) and through the majority of day two (05 May) under an ambient solar
wind environment.  Unsettled field conditions are expected late on day
two (05 May) through midday on day three (06 May) due to the onset of a
negative polarity CH HSS.  Unsettled to active geomagnetic field
conditions are likely beginning at around 1600 UTC on day three (06 May)
due to the anticipated arrival of the 02 May CME.



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