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FXXX12 KWNP 181230

:Product: Forecast Discussion
:Issued: 2015 Apr 18 1230 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 low.  Region 2325 (N04E24, Dai/beta) produced a C1/Sf
flare at 17/1237 UTC and Region 2324 (N19E16, Cki/beta) produced a C1/Sf
flare at 17/1801 UTC, which were the largest events of the period.
Regions 2324, 2325, and 2327 (S10E63, Cso/beta) were relatively stable
throughout the period while Regions 2321 (N11W15, Ekc/beta-gamma) and
2326 (N15W09, Cri/beta) were in decay.

A filament eruption centered near N27W56 was observed in SDO/AIA imagery
between 17/1430-18/0345 UTC, but this event was not reflected in
SOHO/LASCO coronagraph imagery suggesting that the filament was likely

A coronal mass ejection was observed in SOHO/LASCO C2 coronagraph
imagery beginning at 18/0312 UTC off the north-northeast disk but
lacking any discernible events on the visible disk that match the time
and location of the CME, this event is likely associated with activity
on the far-side of the Sun.  No Earth-directed coronal mass ejections
(CMEs) were observed.

Solar activity is expected to be low with a slight chance for M-class
(R1-Minor) flare activity for the next three days (18-20 Apr).

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at moderate to high levels,
reaching a peak flux of 2,090 pfu at 17/1815 UTC.  The greater than 10
MeV proton flux was at background levels throughout the period.

The greater than 2 MeV electron flux is expected to be at moderate to
high levels over the next three days (18-20 Apr).  The greater than 10
MeV proton flux is expected to remain at background levels over the next
three days (18-20 Apr).

Solar Wind

.24 hr Summary...
Solar wind parameters were indicative of the waning influence of a
negative polarity southern polar connected coronal hole high speed
stream (CH HSS).  Solar wind velocities steadily decreased from initial
values near 675 km/s to end-of-period values near 550 km/s.  IMF total
field values were steady between 2-4 nT and Bz reached a maximum
southward component of -3 nT late in the period.  The phi angle was
generally steady in a negative (toward the Sun) solar sector orientation
throughout the period.

Solar wind parameters are expected to continue a steady return to
background levels over days one and two (18-19 Apr).  Solar wind
parameters are expected to become enhanced once again on day three (20
Apr) as a recurrent positive polarity CH HSS becomes geoeffective.


.24 hr Summary...
The geomagnetic field was quiet to unsettled under a nominal solar wind

The geomagnetic field is expected to persist at quiet to unsettled
levels on days one and two (18-19 Apr) with quiet to active conditions
expected on day three (20 Apr) due to the influence of a positive
polarity CH HSS. is the U.S. government's official web portal to all federal, state and local government web resources and services.