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000
FXXX12 KWNP 180031
DAYDIS

:Product: Forecast Discussion
:Issued: 2024 Apr 18 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 at moderate levels. AR 3645 (S10E24, Cai/beta)
produced an M1.6 flare at 17/2208 UTC. AR 3638 (S17E15, Cri/beta) a
C9.0/Sn flare at 17/2004 UTC. Growth was observed in ARs 3633 (S07W78,
Cso/beta), 3643 (S13E34, Fai/beta) and 3646 (N21E59, Cso/beta). The
remaining numbered ARs on the visible disk were either mostly stable or
in gradual decay.

Other activity included a filament eruption observed around 17/0100 UTC
in H-alpha imagery. The approximate 20 degree filament structure was
centered near N40W00. An associated CME was observed off the NW limb at
17/0506 UTC in SOHO/LASCO C3 imagery. Analysis suggested an
Earth-directed component was unlikely. A series of CMEs were observed
off the SE starting around 17/1730 UTC in C2 imagery. These ejecta are
possibly associated with flare activity from a cluster of regions in the
SE quadrant. Analysis is ongoing for these events at the time of this
summary.

.Forecast...
Solar activity is forecast to be moderate, with M-class flares
(R1-R2/Minor-Moderate) likely and a slight chance for an X-class flare
(R3/Strong) over 18-20 Apr.

Energetic Particle

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

.Forecast...
There is a slight chance for a greater than 10 MeV proton event
(S1/Minor) over 18-20 Apr. The greater than 2 MeV electron flux is
expected to continue at normal to moderate levels through 20 Apr.

Solar Wind

.24 hr Summary...
Solar wind parameters continued under the influence of a passing CME.
Solar wind speeds remained low, with values observed from ~345-400 km/s.
Total magnetic field strength was predominantly southward from ~17/0800
UTC to ~17/1730 UTC. The Bz component reached as far south as -8 nT.


.Forecast...
Solar wind enhancements from CMEs that left the Sun over 14-15 Apr are
expected to pass Earth on 18 Apr and should wane over 19 Apr. 20 Apr is
likely to see the onset of influence from a negative polarity CH HSS.

Geospace

.24 hr Summary...
The geomagnetic field ranged from quiet unsettled levels.

.Forecast...
The geomagnetic field is likely to reach G1 (Minor) geomagnetic storm
conditions on 18 Apr due to anticipated arrival of CMEs that left the
Sun on 14 and 15 Apr. Quiet to unsettled conditions are likely over 19
Apr as CME influence wanes. Quiet to unsettled conditions are against
likely on 20 Apr from the anticipated onset of a negative polarity CH
HSS.