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FXXX12 KWNP 310031

:Product: Forecast Discussion
:Issued: 2015 Mar 31 0030 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 was at low levels with C-flare activity from both Regions
2303 (N18, L=065) and 2305 (S10W43, Dho/beta).  The largest flare of the
period was a C4 at 30/0152 from Region 2303 just beyond the NW limb.
Region 2305 produced a C1 flare at 30/1547 UTC.  Slight decay was
observed in the leading spots of Region 2315 (S20W36, Dro/beta) and the
trailing spots in Region 2305.  No Earth-directed coronal mass ejections
were observed.

Solar activity is likely to be at low levels with a slight chance for an
isolated M-class (R1-R2, Minor-Moderate) flare for day one (31 Mar).  An
increased chance for M-class activity is expected by days two and three
(01-02 Apr) as old Regions 2302 (N12, L=189) and 2297 (S17, L=196) are
expected to return.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels. The greater than 10 MeV proton flux at
geosynchronous orbit remained at background levels.

The greater than 2 MeV electron flux at geosynchronous orbit is forecast
to be at normal to moderate levels all three days (31 Mar -02 Apr) The
greater than 10 MeV proton flux at geosynchronous orbit is expected to
be at or near background conditions (Below S1-Minor) for the forecast

Solar Wind

.24 hr Summary...
Solar wind speed at the ACE spacecraft began in the mid-300 km/s range
and declined to the low 300s by the end of the period.  Phi was
negative.  Bz was at or above -5 nT and Bt was less than 7 nT through
the period.

The anticipated negative polarity southern polar coronal hole high speed
solar wind stream has not been detected at the ACE spacecraft yet.
Comparison of the areal extent of the feature with last rotation
suggests the extension has retreated southward by 10-20 degrees.
Additionally, this coronal hole may be lagging the previous rotation by
as much as 2-3 days.  No significant increase in low energy particles
measured by the ACE EPAM instrument has been observed.  The WSA-Enlil
model hints at the negative hole becoming geoeffective on day one (31
Mar), but a separate WSA run shows no high speed stream influence until
day three (02 Apr).  Consequently, it appears unlikely at this time that
the southern high speed stream will become geoeffective.  Instead, the
influence of a positive polarity trans-equatorial coronal hole high
speed stream is anticipated on day three (02 Apr).


.24 hr Summary...
The geomagnetic field was at quiet levels under a nominal solar wind

The absence of the anticipated high speed stream suggests conditions
will remain at quiet to at most active levels through the period.  Weve
maintained a slight chance for minor storm conditions all three days in
the event the southern high speed stream does become geoeffective.
Active conditions are expected to dominate day three (02 Apr) as a
trans-equatorial high speed stream becomes geoeffective. is the U.S. government's official web portal to all federal, state and local government web resources and services.