:Product: Forecast Discussion
:Issued: 2026 Apr 20 1230 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity

.24 hr Summary...
Solar activity reached low levels with an isolated C1.0/Sf flare from
Region 4419 (N15W19, Eko/beta-gamma). This region exhibited minor growth
in overall area, but had slight decay in the number of spots. Aside from
the aforementioned C1 flare, Region 4419 contributed mostly B-level
enhancements during the period. Region 4415 (S18W80, Hsx/alpha) remained
unchanged and was inactive. At approximately 19/1449 UTC, a disappearing
solar filament was noted in GONG H-alpha and GOES SUVI imagery near
N07E31. Subsequent analysis indicated a trajectory well behind Earths
orbit with no impacts expected. No Earth directed CMEs were observed in
coronagraph imagery.

.Forecast...
Solar activity is expected to be at very low levels, with a chance for
isolated C-class activity on 20-22 Apr, primarily due to the flare
potential from Region 4419 and limb activity.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels at 19/1925 UTC with a maximum reading of 1,187 pfu. The
greater than 10 MeV proton flux was at background levels.

.Forecast...
The greater than 2 MeV electron flux is expected to be at moderate to
high levels on 20-22 Apr. The greater than 10 MeV proton flux is
expected to continue at background levels on 20-22 Apr.

Solar Wind

.24 hr Summary...
Solar wind parameters continued to reflect negative polarity CH HSS
influence throughout most of the period. Total field ranged from 2-7 nT,
the Bz component fluctuated between +/-5 nT, and solar wind speeds
gradually decreased from 550 km/s to 400 km/s. At approximately 20/0600
UTC, a weak enhancement was observed in the solar wind environment.
Total field increased slightly to 8 nT, the Bz component simultaneously
saw a southward deflection to -8 nT, and wind speeds increased back to
near 500 km/s. Phi was mostly in a negative orientation, with isolated
oscillations into a positive position.

.Forecast...
Weakening enhanced solar wind conditions are expected on 20-21 Apr as
the CH HSS continues to move from its geoeffective position. A return to
mostly nominal conditions is expected by 22 Apr.

Geospace

.24 hr Summary...
The geomagnetic field was at quiet to active levels as CH HSS influence
persists.

.Forecast...
Mostly quiet to unsettled levels, with isolated active conditions, are
expected on 20-21 Apr as HSS effects diminish. Mostly quiet levels are
expected, with possible unsettled periods on 22 Apr as CH HSS influence
dissipates.