####018002444#### FXXX10 KWNP 021231 DAYTDF :Product: 3-Day Forecast :Issued: 2026 Apr 02 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 5 (NOAA Scale G1). The greatest expected 3 hr Kp for Apr 02-Apr 04 2026 is 5.67 (NOAA Scale G2). NOAA Kp index breakdown Apr 02-Apr 04 2026 Apr 02 Apr 03 Apr 04 00-03UT 4.67 (G1) 4.33 5.33 (G1) 03-06UT 4.00 4.00 4.67 (G1) 06-09UT 5.33 (G1) 3.33 4.00 09-12UT 5.00 (G1) 3.33 3.67 12-15UT 5.67 (G2) 2.67 3.33 15-18UT 3.33 2.33 3.00 18-21UT 3.33 2.33 3.67 21-00UT 4.33 3.67 4.00 Rationale: The geomagnetic field is expected to be at unsettled to G1-G2 (Minor-Moderate) levels through the rest of the UTC day on 02 Apr due to combined CME/CH HSS activity. Glancing CME activity is expected early on 04 Apr causing unsettled to G1 (Minor) storming with a chance for G2 (Moderate) levels. 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 Apr 02-Apr 04 2026 Apr 02 Apr 03 Apr 04 S1 or greater 10% 10% 25% Rationale: There is a slight chance for the greater than 10 MeV proton flux to exceed S1 (Minor) solar radiation storm levels through 03 Apr increasing to a chance on 04 Apr due to possible CME enhancement. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Apr 02-Apr 04 2026 Apr 02 Apr 03 Apr 04 R1-R2 55% 55% 55% R3 or greater 15% 15% 15% Rationale: Solar activity is likely to reach moderate (R1/R2-Minor/Moderate) levels, with slight chance for X-class (R3-Strong) flares through 04 Apr, due primarily to the flare potential of Regions 4404, 4405 and 4409. ####018004031#### FXXX12 KWNP 021231 DAYDIS :Product: Forecast Discussion :Issued: 2026 Apr 02 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. C-class flaring was observed from Regions 4401 (N25W77, Hax/alpha), 4403 (N15W32, Hax/alpha), and 4409 (N02E19, Dri/beta-gamma). The largest flare was a C8.1 at 01/1958 UTC from Region 4409. Slight growth was observed in Region 4409. The rest of the spotted regions were stable or in decay. Other activity included several filament eruptions. The first was an approximate 30 degree filament eruption, centered near S23W57, that began at 01/1800 UTC. An associated CME was observed off the W limb in SOHO/LASCO C2 imagery at 01/1900 UTC. Modeling indicated no Earth-directed component. The second was an approximate 25 degree filament eruption in association with a C6.1 flare at 01/2328 UTC from Region 4403. The bulk of the ejecta appeared NNW is SUVI 304 imagery. An associated asymmetric halo CME was observed in GOES CCOR1 imagery at 01/2345 UTC. Initial model estimates show a glancing blow early on 04 Apr. Confidence is lower in the arrival time due to imagery gaps. .Forecast... Solar activity is likely to reach moderate (R1/R2-Minor/Moderate) levels, with slight chance for X-class (R3-Strong) flares through 04 Apr, due primarily to the flare potential of Regions 4404, 4405 and 4409. Energetic Particle .24 hr Summary... Electrons greater than 2 MeV at geosynchronous orbit reached high levels with a peak flux of 2,587 pfu at 01/1345 UTC before decreasing to normal to moderate levels at 01/1900 UTC. The greater than 10 MeV proton flux at geosynchronous orbit became slightly enhanced to around 1 pfu after 02/0130 UTC, possibly associated with a filament eruption in the NW quadrant around 01/2228 UTC. .Forecast... The greater than 2 MeV electron flux is expected to be at normal to moderate levels on 02 Apr and return to high levels 03 and 04 Apr due to HSS influence. There is a slight chance for the greater than 10 MeV proton flux to exceed S1 (Minor) solar radiation storm levels through 03 Apr increasing to a chance on 04 Apr due to possible CME enhancement. Solar Wind .24 hr Summary... Solar wind parameters began the period under CME influence from the 30 Mar CME. Following the IP shock arrival at 01/1130 UTC, weak enhancements in total field were observed ranging from 3-16 nT coupled with solar wind speeds initially reaching 500 km/s before calming to around 415 km/s. At 01/2005 UTC, a boundary crossing occurred exhibiting a shift into a negative sector. After 01/2300 UTC, total field began to increase reaching a maximum of 17 nT at 02/0729 UTC with Bz reaching a maximum southward deflection of -16 nT. Solar wind speed began to show an increase after 02/0300 UTC indicating the transition into a negative polarity CH HSS. .Forecast... Solar wind parameters are expected to continue to be enhanced under HSS conditions through 04 Apr. Additional enhancements from a glancing blow from the 01 Apr CME are expected late on 03 Apr to early on 04 Apr. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels through 02/0000 UTC followed by active to G1 (Minor) storm conditions due to CME influence combined with the onset of CH HSS activity. .Forecast... The geomagnetic field is expected to be at unsettled to G1-G2 (Minor-Moderate) levels through the rest of the UTC day on 02 Apr due to combined CME/CH HSS activity. Unsettled to active levels are expected on 03 Apr as HSS activity persists. Glancing CME activity is expected early on 04 Apr causing unsettled to G1 (Minor) storming with a chance for G2 (Moderate) levels.