roduct: 3-Day Forecast
:Issued: 2025 Jun 20 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 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Jun 20-Jun 22 2025 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Jun 20-Jun 22 2025

             Jun 20       Jun 21       Jun 22
00-03UT       2.33         2.67         1.67
03-06UT       4.33         2.00         1.33
06-09UT       5.00 (G1)    2.33         1.33
09-12UT       4.33         2.33         1.33
12-15UT       3.33         2.33         1.67
15-18UT       3.33         2.33         1.33
18-21UT       2.33         2.33         1.67
21-00UT       3.67         2.67         1.33

Rationale: An isolated period of G1 (Minor) geomagnetic storms are
likely on 20 Jun due to positive polarity CH HSS influences and possible
influences from a CME that left the Sun on 17 Jun.

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 Jun 20-Jun 22 2025

              Jun 20  Jun 21  Jun 22
S1 or greater   10%     10%     10%

Rationale: There is a slight chance for S1 (Minor) solar radiation
storms over 20-22 Jun.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R3 levels were observed over the past 24
hours. The largest was at Jun 19 2025 2350 UTC.

Radio Blackout Forecast for Jun 20-Jun 22 2025

              Jun 20        Jun 21        Jun 22
R1-R2           65%           65%           65%
R3 or greater   15%           15%           15%

Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected, with a
slight chance for R3 (Strong) or greater events, over 20-22 Jun.



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