3-Day Forecast

Issued: 2026 Jun 18 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center and processed by SpaceWeatherLive.com

A. NOAA Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 2 (below NOAA Scale levels).

The greatest expected 3 hr Kp for Jun 18-Jun 20 2026 is 4 (.00below NOAA Scale levels).

NOAA Kp index breakdown

             Jun 18       Jun 19       Jun 20
00-03UT       2.00         3.00         3.00     
03-06UT       1.67         4.00         3.67     
06-09UT       0.67         3.67         2.67     
09-12UT       2.00         3.00         2.33     
12-15UT       1.67         3.00         2.00     
15-18UT       1.33         2.00         2.00     
18-21UT       1.33         1.67         2.33     
21-00UT       2.67         3.00         3.00     

Rationale

No G1 (Minor) or greater geomagnetic storms are expected. No significant transient or recurrent solar wind features are forecast.

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 18-Jun 20 2026

              Jun 18  Jun 19  Jun 20
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 Jun 18-Jun 20 2026

              Jun 18        Jun 19        Jun 20
R1-R2           10%           15%           15%
R3 or greater    1%            1%            1%

Rationale

There is a slight chance for R1-R2 (Minor-Moderate) radio blackouts through 20 Jun.