####018002122#### FXXX10 KWNP 161231 DAYTDF :Product: 3-Day Forecast :Issued: 2026 Jun 16 1230 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # http://www.swpc.noaa.gov/wwire.html # # 3-Day Forecast # 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 16-Jun 18 2026 is 4.00 (below NOAA Scale levels). NOAA Kp index breakdown Jun 16-Jun 18 2026 Jun 16 Jun 17 Jun 18 00-03UT 2.00 3.00 3.33 03-06UT 1.33 2.00 3.00 06-09UT 1.00 2.00 2.33 09-12UT 1.33 1.67 2.00 12-15UT 1.67 1.33 1.67 15-18UT 1.67 2.67 1.33 18-21UT 1.67 4.00 1.33 21-00UT 2.00 3.00 2.67 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 16-Jun 18 2026 Jun 16 Jun 17 Jun 18 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 16-Jun 18 2026 Jun 16 Jun 17 Jun 18 R1-R2 20% 20% 20% R3 or greater 1% 1% 1% Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio blackouts through 18 Jun. ####018002242#### FXXX12 KWNP 161231 DAYDIS :Product: Forecast Discussion :Issued: 2026 Jun 16 1230 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # http://www.swpc.noaa.gov/wwire.html # # Forecast Discussion # Solar Activity .24 hr Summary... Solar activity was at low levels. The majority of the low level C-class flares were observed at or beyond the NE limb near N08. The largest flare was a C1.8 at 15/1315 UTC from Region 4465 (N08W24, Dai/beta-gamma). Slight growth was observed in this region, particularly in the SE trailing spots along with umbral separation within its larger spots. Region 4464 (S14W70, Hsx/alpha) was in decay as it approached the SW limb. No Earth-directed CMEs were observed. .Forecast... Solar activity is expected to remain at low levels over 16-18 Jun, with a slight chance for M-class (R1-R2/Minor-Moderate) flares. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels, with peak value of 1,488 pfu observed at 15/1740 UTC. The greater than 10 MeV proton flux remained at background levels. .Forecast... The greater than 2 MeV electron flux is likely to reach high levels on 16-17 Jun and decrease to moderate levels on 18 Jun. The greater than 10 MeV proton flux is expected to continue at background levels through 18 Jun. Solar Wind .24 hr Summary... Solar wind parameters were near nominal levels with solar wind speed ranging from approximately 395 to 480 km/s. Total field was at or below 5 nT, with the Bz component between +/- 4 nT. Phi angle was predominantly negative. .Forecast... The solar wind environment is expected to be enhanced on 16-18 Jun due to a possible glancing-blow arrival of a CME that left the Sun on 12 Jun, followed by the onset of positive polarity CH HSS influences. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... Unsettled to active levels are expected on 16-17 Jun due to a possible glancing blow from the 12 Jun CME followed by CH HSS onset. Quiet to unsettled levels are expected on 18 Jun.