3-Day Forecast

Issued: 2024 May 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 6 (NOAA scale G2).

The greatest expected 3 hr Kp for May 18-May 20 2024 is 4 (.00below NOAA Scale levels).

NOAA Kp index breakdown

             May 18       May 19       May 20
00-03UT       3.67         3.33         2.67     
03-06UT       3.33         3.33         2.33     
06-09UT       2.33         4.00         3.67     
09-12UT       3.33         4.00         3.00     
12-15UT       3.00         2.67         3.00     
15-18UT       1.67         2.33         3.33     
18-21UT       1.67         2.00         4.00     
21-00UT       2.33         2.67         4.00     

Rationale

There is a chance for G1 (Minor) geomagnetic storm conditions on 19-20 May due to possible glancing blows from CMEs that left the Sun on 15 and 17 May.

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 May 18-May 20 2024

              May 18  May 19  May 20
S1 or greater   10%     10%     10%

Rationale

There is a slight chance for the greater than 10 MeV protons reaching S1 (Minor) levels on 18-20 May due to the flare potential of Region 3685.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R2 levels were observed over the past 24 hours. The largest was at May 17 2024 2108 UTC.

Radio Blackout Forecast for May 18-May 20 2024

              May 18        May 19        May 20
R1-R2           40%           40%           40%
R3 or greater   10%           10%           10%

Rationale

Solar activity is expected to be low with a good chance for further M-class flares (R1-R2/Minor-Moderate) and a slight chance for an X-class flare (R3/Strong or greater) on 18-20 May.