:Product: 3-Day Forecast
:Issued: 2026 Jun 12 1230 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 5 (NOAA Scale
G1).
The greatest expected 3 hr Kp for Jun 12-Jun 14 2026 is 5.67 (NOAA Scale
G2).

NOAA Kp index breakdown Jun 12-Jun 14 2026

             Jun 12       Jun 13       Jun 14
00-03UT       3.33         4.67 (G1)    4.67 (G1)
03-06UT       3.67         3.33         4.00     
06-09UT       3.67         5.67 (G2)    3.33     
09-12UT       3.33         3.00         3.33     
12-15UT       2.00         4.67 (G1)    2.67     
15-18UT       3.33         5.00 (G1)    2.67     
18-21UT       3.33         4.33         3.67     
21-00UT       4.67 (G1)    4.33         4.00     

Rationale: Geomagnetic field conditions are expected to reach G1 (Minor)
geomagnetic storming on 12 June under anticipated -CH HSS effects. G2
(Moderate) geomagnetic storming levels are likely on 13 June
due to persistent -CH HSS influences in addition to the arrival of CMEs
that left the Sun on 09 and 11 June. G1 (Minor) levels are likely on 14
June as CMEs effects wane.

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 12-Jun 14 2026

              Jun 12  Jun 13  Jun 14
S1 or greater    5%      5%      5%

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 Jun 12-Jun 14 2026

              Jun 12        Jun 13        Jun 14
R1-R2           30%           35%           35%
R3 or greater    5%            5%            5%

Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts
primarily due to the potential of Regions 4464 and 4465. The potential
for activity is anticipated to increase 13-14 June as new regions rotate
into view from the east limb.