FXXX12 KWNP 190031 DAYDIS :Product: Forecast Discussion :Issued: 2026 Mar 19 0030 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 moderate levels following an M2.7 flare at 18/0842 UTC from Region 4392 (S17W12, Csi/beta-gamma). This region has shown sporadic growth and reorganization in the peripheral spots, but has remained relatively unchanged in its magnetic configuration. New Region 4397 (N16E69, Cri/beta) rotated further onto the visible disk and was numbered, yet remained mostly inactive. The remaining regions were relatively stable and quiecent. The M2.7 was accompanied by a tenflare and Type II radio burst with an estimated velocity of 740-860 km/s. An EUV wave is visible in GOES SUVI, along with faint field line movement in the NW quadrant. The associated CME became visible in SOHO LASCO C2 imagery around 18/0936 UTC. Analysis indicated a possible arrival at Earth early on 21 Mar (UTC). Confidence is fairly low with the fit of this event, due to limited C2/C3 coronagraph imagery. .Forecast... Solar activity is expected to be low, with a chance for M-class (R1-R2; Minor-Moderate) level events 19-21 Mar due primarily to the minor instability and variability of Region 4392. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels, with a peak of 2,949 pfu at 18/1715 UTC. The greater than 10 MeV proton flux continued at background levels. .Forecast... The greater than 2 MeV electron flux is likely to continue at high levels again early on 19 Mar. A brief return to normal-moderate levels on 19-20 Mar is expected, due to CME arrival. The greater than 10 MeV proton flux is expected to continue at background values, with a slight chance for an S1 (Minor) level event 19-21 Mar due to possible CME shock enhancement influences. Solar Wind .24 hr Summary... Solar wind parameters reflected near background conditions. Total IMF strength averaged near 4 nT. The Bz component was predominantly northward, with isolated southward deviations to near -4 nT, and solar wind speed gradually decreased from 450 km/s to end the period around 380 km/s. The phi angle was predominantly positive. .Forecast... The solar wind environment is expected to become enhanced on 19 Mar as the 16-17 Mar CMEs are expected to arrive near midday. The disturbed solar environment is likely to continue as CME passage persists into 20 Mar. By 21 Mar, the CME from 18 Mar is expected to arrive in conjunction with the onset of a negative polarity CH HSS. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... The geomagnetic field is expected to become enhanced on 19-21 Mar as multiple CMEs and a negative polarity CH HSS impact Earth. Active to G2 (Moderate) storm levels are likely on 19-20 Mar as CMEs from 16-17 Mar are anticipated to arrive. Additional G2 (Moderate) storm conditions are likely, with G3 (Strong) conditions possible, on 21 Mar as the CME from 18 Mar is expected to arrive in conjunction with the onset of a negative polarity CH HSS.