Solar Information
Solar images from SOHO
The Sun Now
Extreme ultraviolet Imaging Telescope image at 284 Angstrom (to 2 million degrees K)
Michelson Doppler Imager (MDI) image showing sunspots
Magnetogram image showing magnetic field, black and white show opposite polarities
Information from the Space Weather Prediction Center, Boulder, CO
National Oceanic and Atmospheric Administration (NOAA)
Aurora Activity
Solar Cycle
Sun Spot Number Progression
Last 5 cycles Sun Spot Number Progression
Solar Wind
3-day Solar-Geophysical Forecast
:Product: 3-Day Forecast
:Issued: 2025 Apr 17 0030 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
A. NOAA Geomagnetic Activity Observation and Forecast
The greatest observed 3 hr Kp over the past 24 hours was 8 (NOAA Scale
G4).
The greatest expected 3 hr Kp for Apr 17-Apr 19 2025 is 6.33 (NOAA Scale
G2).
NOAA Kp index breakdown Apr 17-Apr 19 2025
Apr 17 Apr 18 Apr 19
00-03UT 6.33 (G2) 3.67 2.67
03-06UT 5.67 (G2) 4.33 2.00
06-09UT 5.33 (G1) 3.00 2.67
09-12UT 4.33 3.00 2.33
12-15UT 3.33 2.67 2.33
15-18UT 3.33 3.00 2.33
18-21UT 3.33 3.00 2.33
21-00UT 3.33 3.00 2.33
Rationale: G1-G2 (Minor-Moderate) geomagnetic storms are expected on 17
Apr due to CME influences.
B. NOAA Solar Radiation Activity Observation and Forecast
Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
below S-scale storm level thresholds.
Solar Radiation Storm Forecast for Apr 17-Apr 19 2025
Apr 17 Apr 18 Apr 19
S1 or greater 1% 1% 1%
Rationale: No S1 (Minor) or greater solar radiation storms are expected.
No significant active region activity favorable for radiation storm
production is forecast.
C. NOAA Radio Blackout Activity and Forecast
No radio blackouts were observed over the past 24 hours.
Radio Blackout Forecast for Apr 17-Apr 19 2025
Apr 17 Apr 18 Apr 19
R1-R2 60% 60% 60%
R3 or greater 10% 10% 10%
Rationale: R1-R2 (Minor-Moderate) or greater radio blackouts are likely
on 17-19 Apr.
