3-Day Forecast

Issued: 2024 May 18 0030 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 5 (.67NOAA scale G2).

NOAA Kp index breakdown

             May 18       May 19       May 20
00-03UT       5.67 (G2)    3.33         2.67     
03-06UT       5.67 (G2)    3.33         2.33     
06-09UT       4.33         4.00         3.67     
09-12UT       4.00         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         3.33     
21-00UT       2.33         2.67         2.33     

Rationale

G2 (Moderate) geomagnetic storms are expected on 18 May due to CME effects. No significant transient or recurrent solar wind features are forecast for 19-20 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%      5%      5%

Rationale

A slight chance for S1-S2 (Minor-Moderate) conditions exists on 18 May due to the flare potential from now departed Region 3664. Probabilities drop to a nominal levels on 19-20 May from the remaining active regions on the Suns visible disk.

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           55%           35%           35%
R3 or greater   25%           10%           10%

Rationale

R1-R2 (Minor-Moderate) conditions are likely on 18 May and a chance for R3 (Strong) exist 18 May. Conditions decay to a chance for R1-R2 conditions and a slight chance for R3 on 19-20 May.