Daily Report

(last updated 31 Mar 2026 23:30 UT)

SUBJ: ASWFC DAILY SOLAR AND GEOPHYSICAL REPORT ISSUED AT 2330UT/31 MARCH 2026 FROM THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE SUMMARY FOR 31 MARCH AND FORECAST FOR 01 APRIL - 03 APRIL STATUS INDICATORS SOL:** YELLOW ** MAG:** RED ** ION: ** YELLOW ** ASWAS SCALE DESCRIPTION: https://bit.ly/3lmaMBx ----------------------------------------------------------- 1A. SOLAR SUMMARY Activity 31 Mar: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 31 Mar: 141/95 1B. SOLAR FORECAST 01 Apr 02 Apr 03 Apr Activity R1-R2 R1-R2 R1-R2 Fadeouts Possible Possible Possible 10.7cm/SSN 145/99 145/99 140/94 COMMENT: Solar flare activity on UT day 31-Mar was R0. There are currently ten Active Regions on the Solar disk. Solar region AR4409 (N03E44, beta) is the newest region, which has developed a number of spots in the last 24 hours. AR4303 (N15W09, beta) has shown some continued east-west separation. AR4404 (N17E10, beta) has seen the development of a number of smaller spots to its north. All other sunspot regions are either stable or in decay. Solar activity is expected to be R1-R2 over 01-Apr to 03-Apr. An Earth directed CME was observed, following an X1.4 flare that occurred on the 30-Mar. It was estimated to arrive at 31/1600UT +/- 10 hours. Signs of its arrival are yet to be seen. S0 solar radiation storm conditions were observed on UT day 31-Mar. S0 solar radiation storm conditions are expected over 01-Apr to 03-Apr. A coronal hole is visible in the southwest solar quadrant and is expected to become geoeffective on the 03-Apr. The solar wind speed on UT day 31-Mar saw a gentle decline from its moderately elevated state, due to an earlier solar wind stream. The solar wind ranged from 460 to 390 km/s and is currently at 400 km/s. The peak total interplanetary field strength (IMF, Bt) was 6 nT and the north-south IMF component range (Bz) was +5 to -4 nT. The solar wind speed is expected to increase over the next three days, due to the anticipated arrival of a CME and then from solar wind influences on the 03-Apr due to a coronal hole. ----------------------------------------------------------- 2A. MAGNETIC SUMMARY Geomagnetic field for Australian Region 31 Mar: G0 Estimated Indices 31 Mar : A K Australian Region 4 12122111 Cocos Island 2 11211100 Darwin 6 22222112 Townsville 5 22122112 Learmonth - -------- Alice Springs 5 12122112 Gingin 5 22222210 Canberra 4 12122111 Kennaook Cape Grim 5 12122211 Hobart 5 12122211 Estimated Antarctic Regional K Indices 31 Mar : Macquarie Island 5 11222310 Casey 11 34332211 Mawson 13 23222315 Observed Regional daily pc3 Indices 31 Mar : Darwin 4 (Quiet) Townsville 0 (Quiet) Learmonth NA Alice Springs 0 (Quiet) Gingin 2 (Quiet) Canberra 2 (Quiet) Hobart 2 (Quiet) Pc3 pulsations are high frequency (10-45 second period) variations of the Earths magnetic field. Daily pc3-indices are the daily sum of 20 minute pc3-indices for that station and have been shown to be well correlated with rejection of high resolution aeromagnetic survey flight-line data. NOTE: Indices may have been generated from data obtained in cooperation with the following organisations: Geoscience Australia, University of Newcastle Space Physics Group, Australian Government Antarctic Division and International Center for Space Weather Science and Education, Japan. Estimated AFr/Ap Indices 31 Mar : A Fredericksburg 16 Planetary 30 Observed AFr/Ap Indices 30 Mar : A K Fredericksburg 11 Planetary 12 3333 3222 2B. MAGNETIC FORECAST Date Ap Conditions 01 Apr 46 G2-G3 02 Apr 29 G1-G2 03 Apr 29 G1-G2 COMMENT: ASWFC Geomagnetic Warning 22 was issued on 31 March and is current for 31 Mar to 2 Apr. G0 geomagnetic conditions were observed in the Australian region on UT day 31-Mar. G0 geomagnetic conditions were observed in the Antarctic region. An Earth directed CME was anticipated to arrive at approximately 31/1600UT +/- 10 hours, but has yet to do so. This is expected to give rise to G2-G3 conditions on 01-Apr, giving way to G1-G2 on 02-Apr. G1-G2 conditions are expected on the 03-Apr, with a coronal hole high speed wind stream expected to bolster waning CME effects. ----------------------------------------------------------- 3A. GLOBAL HF PROPAGATION SUMMARY Latitude Band Date Low Middle High 31 Mar Normal Normal Normal PCA Event : No event. 3B. GLOBAL HF PROPAGATION FORECAST Latitude Band Date Low Middle High 01 Apr Poor Poor Poor 02 Apr Fair Fair-poor Poor 03 Apr Fair Fair-poor Poor COMMENT: HF radio propagation conditions on UT day 31-Mar were normal. HF conditions are expected to be degraded during the next three days at all latitudes, due to a CME anticipated to now arrive on the 01-Apr, followed by connection with a coronal hole on the 03-Apr. Isolated fadeouts are possible, due to flaring activity. ----------------------------------------------------------- 4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY Date T index 31 Mar 108 Observed Australian Regional MUFs Cocos Island Region: Near predicted monthly values during local day. Enhanced by 20% during local night. Niue Island Region: Enhanced by 15% during local day. Enhanced by 15% during local night. Northern Australian Region: Near predicted monthly values during local day. Enhanced by 15% during local night. Southern Australian Region: Near predicted monthly values. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Feb 98 Mar 87 Apr 85 4B. AUSTRALIAN REGION IONOSPHERIC FORECAST Date T index MUFs 01 Apr 60 20 to 30% below predicted monthly values 02 Apr 60 20 to 30% below predicted monthly values 03 Apr 60 20 to 30% below predicted monthly values COMMENT: ASWFC Preliminary HF Communications Warning 30 was issued on 31 March and is current for 31 Mar to 2 Apr. Maximum usable frequencies (MUFs) in the Australian region on UT day 31-Mar were generally near predicted values with enhancements of up to 15% during local night in the northern Australian region. Spread F was observed at Hobart during the local night. Sporadic E was also seen during the first half of the 31-Mar at Niue. MUFs are expected to be up to 30% depressed over 01-Apr to 03-Apr. Ionospheric depression is anticipated due to a CME expected to now arrive on the 01-Apr, followed by connection with a coronal hole on the 03-Apr. Isolated fadeouts are possible, due to flaring activity. ----------------------------------------------------------- 5. SPACE ENVIRONMENT SUMMARY GOES satellite data for 30 Mar Daily Proton Fluence >1 MeV: 2.9E+05 Daily Proton Fluence >10 MeV: 1.6E+04 Daily Electron Fluence >2 MeV: 4.70E+07 (normal fluence) Electron Fluence Daily Deep Dielectric Discharge Probability: 6% Fluence (flux accumulation over 24hrs)/ cm2-ster-day. X-ray background: C1.0 DSCOVR Satellite Solar Wind Day Averaged Data for 30 Mar Speed: 450 km/sec Density: 2.2 p/cc Temp: 124000 K Bz: 1 nT (Courtesy Space Weather Prediction Center, Boulder USA) -----------------------------------------------------------